Your characters, Anshin, have a valid excuse -- I admit, I have two rather expensive level 3s right now that are top-end and just stockpiling XP, but the only reason I have them there is to have a basis for potentially dual-tactics play (Takedown is a Heavy Assault Vehicle, Piranacon a Sea Monster); both are dedicated rammers, but I want the XP to make a go of potentially opening up Strafe and getting a bit of Firepower as well.
I admit, I'm a little impatient, but mostly because I'm in that "tweener" stage, as it were -- I'm still considered low-level in a sense (I personally consider 0-4 low-level, 5-7 mid-level and 8+ high-level), but I'm wanting to get into the mid-level/high-level play more. And I can't do that when I have to contend with characters that have 6M+ xp and could make really good level 5s, if not low-end (upgrade-wise) level 6s with plenty of room to develop, but are only using just a tetch over 4M in their builds at best to make high-cost builds and stay in level 4 to whore XP. Personally, I think it's like Burn put it -- they're being cowards who are afraid of being in higher-level play because they think they won't be able to do nearly as good as they are by whoring XP off low-levels with their "uber-build".
Edit: Case in point -- http://www.seibertron.com/heavymetalwar ... r_id=91445
. 4.2M build, 5.5M total XP. Well more than enough to be a top-end level 5 with Avoid in the mix, but refuses utterly.