I'm really sick of getting stuck with a group of L55s that skip everything, five times this week we've had a L55 tank in a group with lower levels that left when we asked to kill the other bosses or do the bonus because we need the XP or gear , really wish they would stop L55s from doing 50 flashpoints with under 55s. After a 20+ minute wait for a tank on Jedi Covenant I really don't want one to drop because he wants to just get it done fast and can't be bothered to explain to people how an EASY fight is done
The gear from the HM lvl 50 FPs becomes obsolete very quickly and as for XP, there are a myriad of ways to get extra XP; it's easy to get from 50 to 55 without running any FPs.
Also, people at level 55 want to run the lvl 50 FPs to get basic comms to get isotope-5 to then craft/trade for the 72 gear. There are generally more lvl 55s running the lvl 50 FPs than there are people at levels 50-55 from what I've seen.
Even if you skip some of the bosses, you're still going to get 2-3 loot drops in the FP and the level 55 isn't going to need any of them. Besides, the drops from the lvl 50 HM FPs isn't that great anyway; you're better off spending planetary comms to get the gear from Makeb.
If you want to run a FP with a tank that wants to do all the content, the best approach would be to ask in general chat on the Fleet.
The problem is more that there are not enough people rolling tank classes; my lvl 55 Rep toon always finds a group immediately for both lvl 50 and 55 FPs