I don't think the solution is to nerf high level gear for low level characters. I think if you actually manage to get that kind of gear at low level, you've essentially earned it.

What I see as the problem is that most good limited lower level gear becomes the staple re-gear for heroes before they head off to get their better stuff... Thus preventing that gear from actually circulating amongst lowbies/midbies. Potential solutions here are to either change how such gear is limited, or to make it less useful to higher level characters and more useful to lower level characters. Good examples of gear that already works in that manner are both the Soul Drain item available to necromancers, and the questy pathfinding boots.

Everything else you've said I can agree with, save for invisibility. Getting detect invis is pretty much laughable these days, so your change only actually affects wannabe rager applicants and applicants pre-25 anyhow.