I managed to do quite a few:
Linienni needed a respec anyway, for playability, but I got her to 32 to unslot enhancers as well.
Siren of the Deep didn't actually change any powers or slots, but needed the cash. Got her to 37.
K'teri did need the cash, and did change some powers although she didn't really need to. I got her to 37 and swapped out quicksand for radiation infection, and super speed for fly, to go with some insect wings I bought her with all her money. So, er, she still needs the cash she would have had if I hadn't blown it all on pretty bug wings. c.c
Monique Snowflake is a character I hate to play because of her name... the plan was to respec her into a teamy shield-based build, but I decided 'hell with that' and just ditched her AoEs for more team-and-self-benefitting toggles. Which means she's actually worse than ever -- slotting more endrdx into the toggles didn't make up for having more of them, and I had to pull the slots out of her attacks. Oy!
I also respecced a couple characters in their teens just because.
In the process of getting Siren up to 37, I did a bunch of the new missions from the Rikti War Zone. Rikti are tough opponents... some people say Malta and Rularuu are harder, and they don't have anything to compare to a Master Illusionist, but overall they're tricksy and resilient foes, with teleporters, portals, support troops with am and bubbles and healing, and plenty of mez.
Unfortunately, they drop tech. EVERYONE'S doing the rikti invasions or the new rikti missions in the new rikti war zone, so everyone's getting tech salvage. Magic salvage is *really really expensive*, and some types are just gone. At one point, there were no Fortunes available for any price... and Fortune is *common* salvage.
I guess we know the Rikti's real plan -- distract everyone into fighting them, pass out worthless tech salvage, and ruin the economy to prevent earthly heroes from building IOs!