So I've been thinking about it. . .

At first I was very turned off by the idea of another static in my wormhole, but the more I think about it the more I'm starting to warm up to the idea. That being said, it's not going to do anything to help players become more active in C4 space. Just from the law of averages, it might lead to more random accidental encounters just from the increased travel-through they're likely to see, but balance that against the increased need to turtle to survive and the likelihood that many smaller corps will be moving out, you get a lot of empty space.

CCP, if you want larger corps to move in, or you want the current C4 residents to do more pvp, then you need to give us a chance to replace what we lose. As it stands right now, it takes ages to replace even the bare minimum fleet for running the combat sites in there. Whether you're looking at 3 RR Domis, a lone Marauder, or a flock of tengu, the cost for replacing lost ships is too high for C4 corps to remain viable without turtling up.

Say your bare minimum Dominix team is somehow able to run the sites with 3 ships totalling 300m each after fittings. . .
In order to afford a replacement fleet, you'd need to run between 10 and 15 Barracks depending on salvage. Let's say it takes you two weeks to get that many spawned (in my experience, it takes longer). That's about 260 mil in fuel at current Jita prices for one stick. That adds 3 more sites onto the calculation.

Assuming you have NO other expenses, your break even is 13-18 of the best sites in the class before you can afford to lose one bare minimum fleet. Keep in mind, that fleet just barely squeaks by on those sites. The payout for the work just isn't there. People turtle up, not because they're afraid of dying, but because they can't afford to replace their ships on that kind of income.

TL/DR: If you want more activity in C4s, then you need to provide a living wage, yo. People stick to c3s and c5s, avoiding c4s not because of logistics, but because of income potential

So screw everyone who lives in a C4 currently, they should all move out so the T3 blobs can move in? While everyone else is looking at this as 'how to benefit both sides' all you want is PvP and screw anyone who doesn't....

You forget that without people running sites you lose targets, the more people who leave wormhole the less people there are to shoot at. So if all you care about is getting kills for yourself at least don't be so short sighted as to think that kicking all current C4 holders out is a good thing.