Control: "Control is internal. It is the Jedi's ability to recognize the Force in himself and to use it to his benefit."
1. Force concealment. Probably not, the chances of both events happening on the same day is rather slim. All we know is that the death of the Son would result in the Children no longer being concealed, and that the Son was actively concealing him. How this was achieved we do not know, likely through some kind of Sith Magic that drew on their strength. This at least indicates that the Sith Emperor was capable of concealing his presence, but this is a given as the basic levels of this skill were accessible to most - but the idea that it surpassed Caedus' unprecedented talent in the field is very slim indeed.
Again I don't think this is grounds for disputing Caedus' superiority in this category. You may call it loop holes, I call it weak evidence being accepted at face value. The grounds that the Sith Emperor was above-average in this field are slim, the grounds that he was superior are entirely non-existent and I'm afraid pure speculation. Speculation unfortunately does not cut it on this thread, we are dealing in ground realities.
Sense: "Sense involves the next step, in which the Jedi recognizes the force in the universe outside oneself."
1. Foresight: I am no expert on Caedus, and his Wookiee page is lacking, so you will have to look to Rayla for examples on the matter. Not that that will help prove the Sith Emperor's superiority.
As for your list of Sidious' lack of foresight, I pointed out to you that it is logically flawed to show examples of Sidious not predicting things because unlike the Sith Emperor he has displayed an exceptional ability in foresight. So I am confused as to why you persist. Nobody is infallible and we cannot expect them to be, but that doesn't change the fact that foresight is a Force power and one that should be considered. Being able to perceive the future with such accuracy - which you kindly point out is often difficult to see - points to an incredibly strong connection to the Force. Especially given the fact that as a Sith Lord who draws on the dark side his ability to see the future should feasibly be diminished, yet it was not - his mastery over the Force is the reason for this.
Also you might want to take note of this:
Using the powers of Revan and his Voss host to gaze into the future, the Emperor saw the possibility of his own death at the hands of that Jedi.
--Sourced from various codex entries.
This would seem to point to the Sith Emperor being reliant on others for his visions. We can't make the unsupported assumption that by tapping into the Voss and Revan that he gained their powers in foresight. Else he would have had no further need of them, yet he continued to use the Voss for decades and Revan for centuries. Obviously he did not inherit their powers, which for the record is a process not supported by Star Wars mythos.
Again none of the arguments you present give me reason to reassess Caedus' superiority. Even if we accept that the Sith Emperor had an above-average ability in foresight we still have no grounds for assuming that he surpassed Caedus' unprecedented ability in foresight.
Alter: "Alter is the third and most difficult area to master, for it involves the student's ability to modify the Force and redistribute its energies."
1. Telekinesis: if they had armies on the ground the fighting would have stopped with the death of the DC members. This is how it works, once one or both of the challengers has died or surrendered the Kaggath is over. If you had played the SI storyline you would no that if the DC killed Thanaton and Nox during either of their confrontations, the battle would have ended. Regardless of the fact that they both possessed power bases. Furthermore that is just one possibility, how do you know that it was instant destruction? That it was performed with telekinesis at all? Do you think they both just stood in front of the Citadel and tore it down? Really? You have no idea what happened. All you know is that somehow, someway two DC members managed to destroy the Citadel after a prolonged Kaggath, a rite of Sith that goes beyond the participating individuals. I'm afraid this is not grounds for claiming that the Sith Emperor was a superior telekinetic to Caedus - really the link is so very very tenuous. Even you must realise this. I await evidence of the Sith Emperor perfoming such feats in person.
2. Lightning: My point is that in order to incapacitate a powerful Force user instantaneously without them being capable of deflecting said power, the Sith Emperor requires time to prepare. Noting that any Force user more powerful than the other is capable of overwhelming the latter with a stream of lightning, and that by penetrating their Force barriers the conclusion will always be a charred husk. Indeed if Caedus had been in the Sith Emperor position, Revan - being less powerful - would have eventually given way and died. In such a sense it only proves that the Sith Emperor is more powerful than Revan, not that the Sith Emperor can one-shot Jedi of Revan's caliber, he can't.
3. Mind Control: Funny, if you hadn't been so hell bent on disagreeing and attempting to degrade every single one of my points you might have noticed that I gave the Sith Emperor the advantage in this field. Unfortunately one advantage against many disadvantages is not enough to secure him the #2 spot.
As for your other points, the DC were not in the presence of the Emperor, they were outside the Citadel and likely did not expect an attack at that point - given the fact that their were no hostiles 'in-range' so to speak. But again we don't actually know the nature of this power, it could have (and likely was given the emphasis on the weather) been Alter environment which not only would have been bolstered by the lightning storms, but would have bypassed their Force barriers (if any were present) as natural lightning is a non-Force based attack. And that is without taking into account the fact that the Sith Emperor could have spent a long time in preparation, and possibly even drawn on the dark side nexus of the planet to bolster his power. Something he could have done in many situations for that matter. Also concerning your little quote, I think it is you who need to read it and in particular take note of that very key word: rumored. Again not taking into account the already present dark side nexus surrounding the planet.
But in the end I'm not sure what your point is here, being able to inadvertently affect the weather is not exactly a remarkable accomplishment. In fact he has been outclassed by the likes of Darth Plagueis who's simply presence on a planet resulted in a weather change - not dark side nexus needed.
Again we find ourselves entering the realm of subjective speculation, we have no hard facts that point to the Sith Emperor being a superior telekinetic, just vague connections between even vaguer happenings. Neither do we have any grounds that the Sith Emperor is a superior wielder of Force lightning, as his instantaneous applications of the power do not in anyway surpass Caedus. No, in the end we cannot say that there are anything other than equals in this category. With any edge being give to Caedus due to his superior ability in telekinesis and Force illusions.
And concerning my 'logic' my logic is to make comparison. Not wave about abilities which we cannot make a comparison with and therefore cannot gauge who is superior in the field i.e. pointless bickering. Indeed it would be like claiming that X is better than Y at football despite never actually witnessing Y play football. That I'm afraid is the 'logic' you are trying to enforce here. Indeed you'll find your desire to resort to one-upmanship followed by a degradation of arguments presented as has been done in the past will go unslaked.
Indeed this is the beauty of this system, in the end we only need one or two feats from each category to gauge who is superior in said category, as they all rely on similar applications of power. Someone with a strong foresight is going to have a strong Force sense, just like a powerful telekinetic is likely to be a powerful wielder of Force lightning. In the end we are a gauging one thing, the ability to wield the Force. And we do not have to take absolutely everything into account to reach a more than reasonable conclusion.