Watching The Force Awakens, it seems like blaster technology has noticeably improved. Many blasters seem to create small explosions capable of affecting multiple targets at a time.
Not really. The only blaster that is really more powerful is Chewbacca's crossbow shaped one.....that one holds a very very very very strong punch even so strong that a specific Solo is surprised by it!
That aside the only thing that is new is that even shoulder wounds (right in the beginning a storm trooper suffered one) are lethal within seconds (although there is a counter example.....but Force users are different anyways). That thing I would count as artistic freedom there though.
So all in all: Nope blasters are as strong as always and Chewie really should be hired to upgrade those of the resistance to Wookiee levels!