Extending the duration of Aim/Buildup would be problematical. The buffs are powerful so they aren't meant to be constantly available. They're still up often enough to be useful, especially against 2 or more bosses.
If someone in the raid is having issues with all the flashy powers going off then it should be up to them to turn down their particle counts in the options. Asking a player to modify their powersets is dickish.
I'm wondering if that wasn't going to be the lead in to the promised space missions that never came. The Space Port was supposed to be in Steel Canyon IIRC.
I kind of did the opposite and 3 slotted it with Heal/Absorb. I wasn't really have end problems. If I add a slot for Endurance Mods it'll probably just get the Performance Shifter proc.
He's for something that was being worked on before the game shutdown. This is all I could find:
https://paragonwiki.com/wiki/Colonel_Taggard
Edit: Well , ok he was also a real person who led the 12th Pennsylvania Reserves in 1861.
There's already a sliding accuracy bonus from level 1-20 called Beginner's Luck. It starts large at +15% toHit and gradually decreases every level. I suspect what Jeuraud ran into was a named Boss scaled down to a Lt.