I don't even care about that stuff, I just want to use my controller without having to be tied to steam, or buy games for non steam stores. I can do that now but the windows drivers that communities are working on is still being fleshed out. I can at least use GOG Galaxy 2.0 very well for pretty much all of my games thanks to GloSC (global steam controller app). That thing is a life saver, putting in major work.
Mods: I do them well without Steam. I don't even think I mod my games with Steam. Steam modding seem limited going by Saints Row, and Skyrim. It's much better to mod those two outside of Steam.
Forums: I always think this is a bit of a joke. People seem to love Steam Forums. I never use them. Google searches for issues, or tips is far better. You get forums (excluding Steam's for comparison sake), Reddits, tweets, game dev websites forums and information, video demonstrations via youtube, twitch, etc. It's natural, and easy.
Controller: Right now Steam has Steam Controller locked down, not totally, there's a good alternative that allow you to fully use it without steam booted, but it's a work in progress. For other controllers, I half wish my steam controllers were dead so I cold dive into reWASD. Also there are a ton of good controller profilers out there. I've always used them, and now they are far better than they ever were.
Games activated on steam still have to deal with Steam's customer service, they are a lot faster replying now at least, but my previous experience with them got no ticket responses, for a big company like Valve. I got tired of waiting whenever I needed their help and they just never responded, I'm talking weeks even months iirc I ended up closing the tickets because I moved on (the issues were with steam and mistaken money put in the wallet two times because of a laggy experience on their site so I thought nothing went through. Eventually I made use of the money in the wallet, and vowed to avoid spending money on their app. Amazon and EA spoiled me on customer service.). The new system or whatever they have in place at least get you a response from something or someone telling you that your ticket is being reviewed and it's not ignored somewhere.