A rent increase is not the same as a gentrification crisis.

The fact is, this issue is not a product of a supply issue. There is plenty of housing in Berlin, if you're willing to live in a non-trendy area and maybe take an extra stop or two on the train. In places like the Bay Area, there simply is no supply, and therefore there is a crisis.

I assume Wedding gets hit by the price hike pretty badly because it's next to Mitte and the rents were particularly low despite the central location. As long as people don't get displaced, I don't see it as a bad thing, Wedding still looks kinda sketchy and will benefit from more affluent residents in the long run.

Not sure how many do this, but you're basically describing my situation, 8 min commute to Mitte, and relatively cheap. Due to the rent control, rents only jump after tenants change. An identical flat to mine, below me, was just now online available for rent for about 20% more than my rent is - and got rented out within a month, so there's demand.

I don't think there's a fear for displacement yet, there's quite a few plots to build up, or abandoned places that are torn down (e.g. Stattbad), and a bunch of new modern apt buildings coming up. But for now, it looks like Neukölln is the more desirable next-hip-thing.