In terms of story telling, if there's not a crisis what else are you talking about? It's not as interesting to see someone just going about their day. The drama is in the crisis.
I agree. You need crisis to further character but there are all kinds of crisis. Identity isnt the only one but somehow Star Trek seems to have gotten stuck on this plot point. It started a little with Spock but was manageable. Imo it went off the rails with Data. Then the writers hop over the Voyager and the rut is now a canyon by season 6.
DS9 suffers from it too in Odo and Kira, then later Dax but it doesn't totally monopolize the show because you have political crisis as well.