Given those constraints, they are successfully delivering more of the same general quality. Whether it will all add up to pack the same kind of punch as Season 2 I kind of doubt, but it's creditably done. They all lost their massively useful powers in the Christmas Special, and got less useful new ones, which was the only way forward.
Episode 1 introduced the replacement for Nathan - Rudie, who says all the offensive things that Nathan used to, but is more tormented by self-doubt, which he projects as a living alter-ego (as in the Red Dwarf 'Confidence and Paranoia' episode). I thought this was one of those episodes where the work of setting up a series happens. Never the most scintillating.
Episode 2 was about Curtis, whose new power is to become a woman, and it was fairly sensible about female sexuality and date rape and consent. The actress who played girl-Curtis was good. Closer to the real Misfits thing.
Episode 3 was about a comic-book artist whose drawings come true, letting him control other people. He uses this power to control Simon, who he is obsessed with. In the end he makes Simon kill him. This seems like a proper Misfits episode.
So. I have confidence that the writers and actors understand what they should be doing, but I am not sure it's even possible to replicate the charge of the first two seasons. I'll certainly continue to watch it and enjoy it though.