We'll have a blocksize increase after segwit. It's not Core's fault that miners are fucking stupid and are not signaling for segwit as soon as possible. Segwit is needed before we increase the blocksize.
It wouldn't actually be a good idea to activate Segwit now from the miners perspective, or even proponents of Segwit. Segwit ready nodes are just about 50% of the network now, and there's too high a risk that a Segwit block generated today would not propagate around the Bitcoin network sufficiently well with only 50% of nodes capable to relay the Witness data (i.e. the extra 3MB of blockspace that would be available).
To put it another way, an attacker might try to exploit this effect by amplifying it somehow. That could mean network disruption serious enough to start attributing blame to the design approach of Segwit, when in fact it was caused by careless rollout.
I'm not sure what percentage of Segwit nodes major miners would deem safe, but it's a reasonable assumption that it's > 50%.
Segwit provides a blocksize increase. Putting that aside, I would welcome a properly written HF proposal that builds upon Segwit. However, I would not be willing to accept something that reduces the block size limit (as proposed recently by luke-jr).
That's not a very good description of what Luke's (latest) Hard Fork plan actually is; the blocksize limit depends on absolute blockheights in his proposal, and so whether or not the blocks are bigger than 1MB or smaller depends on
when the fork is activated.
If that hard fork activated tomorrow, we'd have 300 KB blocks. But that's very unlikely to actually happen. By the time a fork proposal like that activated, it could easily have reached the stage of progress where the blocksize is bigger than 1MB (I think Luke is using the 17% per year "technological growth" factor that Pieter Wuille did in BIP103)
Don't get me wrong, I'm not totally convinced myself, Luke's ideas are often a little eccentric superficially. But let's not forget that he's contributed useful stuff that wasn't considered too "out there", not least a soft-fork for Segwit, which not everyone thought was possible beforehand.