The OP asked about the future, so clearly, next month is part of the near future, right? You just need to bring your pessimistic venom in here too, huh.
To the OP, as far as ROMs go, WP7 wasn't designed with that in mind, and to be honest, you really don't need custom ROMs, as they really wouldn't add anything. The UI, as I'm sure even people like N8ter would agree, is second to none in terms of efficiency, and with time, the features will greatly increase (like the Mango live tiles, the concept of Nokia 3D tiles). Where in WM6.5 we NEEDED to flash to make the phone usable, we don't need that with WP7.
As for apps, as of now, the apps are pushing the allowed apis to their limits for the most part. Microsoft was pretty shelled with their apis on the initial release, and that was due to missing functionality. With the Mango api, you'll see a slew of apps hit the marketplace, big named apps such as Skype to be more specific as the platform will flash much more impressive features. In the next month and a half to two months we'll get an idea as to what ideas will start forming with these new apis, but look for the releases to be huge.
Games are about to take off in an even bigger way too, with big names like Hydro Thunder and Angry Birds starting to come out, and I see more coming with time, and available features.
With that being said, I suggest you try the phone out for yourself, as it isn't for everybody. If you're somebody who insists on having a registry editor just *because* you feel the need to look at one, then this isn't for you. Or if you feel you need full device control for absolutely no reason, this isn't for you. But if you enjoy a phone that just works, and does what it's currently capable of extremely well, then you've got a winner.