I don't believe that any of the changes I've suggested would effect combat at the "basic" level.
Since it would be a special shard, geared towards combat, it could have other differences, things that you would classify as "things that would make the game better from a fresh start", but would piss off a lot of people.
I don't much care for the idea of a new shard as I think we've got enough space as it is.
I think this shard should be much much smaller than the others, so it wouldn't add much space. I also think it should not allow spawning in it and maybe even having restrictions about which creeps can cross (e.g. crossing creeps lose 4000 hits) or having some boosted portal keepers, so you have to earn your place in it. Or maybe portals to it would be short lived and only appear among ruins of Lv 5 strongholds.
Really I just think it's a bit too easy to make an inpenitrable room on the main server right now, and I feel the main server shouldn't be as stale as it is, especially compared to days of old.
Personally, I like the MMO better now, more peaceful.