The choice is yours wether to do them or not. I like them personally and apart from the few that are at the very end of a zones progression its not been hard to find a group.

As far as zones being empty once people have a level 50 goes, I'm not so sure thats going to be the case and even if it is level with a guid mate or 3. If your playing solo and your not in a guild this is a mmo its designed for group play and your missing a valuable part of the game.

Last but not least they are a reasonably rich source of BoE blues so go back when you can solo them and you can get a nice bunch of blues for your alts or to sell.

The Heroic Quests are fine as it is but in my opinion some of them could have started earlier specially on the Bonus Ops. I had very hard time finding the Heroic quests for Nar shadaar which starts around level 28, and specially Alderaan Bonus series along with maybe Balmorra aswell. There are usually from 3-5 heroic quests piled up on each bonus series where you can hardly find anyone doing it due to the level it starts. Balmorra Bonus quests doesn't start untill you are 38, and you usually get out of the planet around 35-36.

Should the Heroic Quests start around the level you are finishing the planet it could have been easier to find groups, like Taris. It is really a shame since the rewards are usually epic quality mods and by the time you are comming back to do them when you outlevel the content by ALOT, the rewards are not that usefull (well you can pass to your alts, since its Bind on Equip) let alone the experience.

Currently I was fortuante enough to finish almost all the heroic quests on my main (46 sage), except the one in Alderaan. Simply put, no one else is doing it either they don't know it or they exist or they are simply skipping it. It gets worse when you are higher that you can't even find people on Heroics that you pick on your way leveling. I want to do them all at least on my first character, just that its quite hard to do the optional quests at the current state.

You also have not answered what's wrong with my second suggestion unsurprisingly.

Yes I did. Apparently you just chose to zoom in on one sentence that apparently pissed you off, and skipped the majority of my post where I explained the problem.