I would like to focus on the fact that the drop matches the bosses severity, Dr Lorrick is one of the harder bosses in the entire flashpoint system, he is complex both on a mechanic level and on a pure damage in + damage out level. However the other two bosses in the flashpoint don't match that in any way, the first droid don't do any heavy load of damage, the only problem with him is the mechanics, and on the second boss you only have to deal with a great deal of unavoidable damage, however few problematic mechanics.
I would say that most flashpoint bosses matches the severity level of Story Mode EV/KP, however I wouldn't say that Dr Lorrick matches Soa in Hardmode as well as Toth and Zorn/Terror from Beyond in Storymode (the other place were chest drops). So, in my opinion the loot from LI is actually very good considering what drops and what else you need to do in order to obtain the same loot.
LR-5 is mostly about the whole team handle things well, sure he does not do huge damage unless you don't interrupt his fireaoe but there are a lot of sources which could cause damage, if there are melee DPS it could get more difficult. It's no doubt harder than all of the Tier 1 HM and around the same level as Sav-Rak/Lorrick.
Sav Rak is not just about avoid damage, it has a very tight enrage timer at least since 1.5. Even Columi could get him to enrage sometimes, the gear requirement is even higher than Lorrick.
Overall, the 3 bosses are around the same level, just different mechanics and challenges.