Warden

I've never been able to soul extract pets I've released due to corpses disappearing immediately, but I'm hopping on right now and will let you know if I find anything out.

It's really not that bad if you have good keybinds! I personally use http://web.archive.org/web/20120904222729/http://boards.cityofheroes.com/showthread.php?t=117256 and it works like a charm, making it really easy to select groups of pets and tell them to do exactly what you want. In particular having quick access to pet command binds makes it really easy to swap in and out of bodyguard mode, reduces the chance that your pets will run off and aggro other mobs on its own, and can improve the speed at which you set priority targets or just spread out your forces. I don't think you HAVE to do it to be viable or anything, but it smoothed my gameplay out a lot and made it very enjoyable to manage my personal army :)

As a necro, I do it quite a lot. Not sure if it's the same for other MMs, but my pets have pretty specific niches and I try my best to make use of their skillsets when engaging enemies (when i'm soloing, team play tends to be more relaxed/casual). Zombies are more or less fodder that does ok damage. I'll send them in to tie up groups of enemies i don't care about, but don't want beating on my face or my other pets. Grave knights are the big damage dealers. They have cc and tons of dps, so i put them on priority targets to take down ASAP and primarily focus on supporting them. Lich has tons of debuffs and CC, so that's what I primarily use him for. I'll set him in the direction of enemies that, while not fodder nor currently priority, can/will be priority once my grave knights clean up whatever they're currently killing. He usually keeps them locked down, and will blast them with dark damage which helps debuff them and get them ready for combat with the GKs. He's pretty good at staying alive, himself, so there's usually no issue letting him deal with 3-4 enemies by himself. I think it just depends on your playstyle though. Sometimes brute-force sending all of your pets to attack a single guy is totally worth doing and possibly even optimal. But for solo play I like to strategize.