We did something, it is Segwit. I think it is tomorrow when it should activate.

#1) I don't know about this. Some cryptos do this to get rid of mining pools. There might be some drawbacks, but as other proposals it would definitively require a hard-fork and we know that this can take a lot of time.
#2) I don't think that differences between blocks have as much to do with daily changes in hashpower as just with luck. I don't think that this would help at all. This readjustments are representing the change in network's hashrate and I don't think that there is a significant change in hashrate on a daily basis.
#3) Woah there, this sounds like centralization to me. Nodes are represented by IP addresses and that means that whoever can get most IP addresses has that 1%. ISPs and therefore the governments would love this.
#4) Any suggestions on how to do this? I think that reducing block time would just increase the rate at which disk is accessed.