Surivors Speed

I understand where you're coming from with this but realistically changing the survivor speed at all would make half the roster redundant. For example, a measly trapper moves at 4.6m/s, this is the default speed for killer and is only 15% faster than a survivor, as it is he has a larger hitbox meaning hugging objects is far harder for him than a survivor. This means he can take a fair amount of time just to catch up to a survivor going around a rock really well.

Around the release of MFT it had an effect far better than now where you simply got 3% haste when injured, 3% isn't a lot on paper but it was painful for any M1 killer to catch up to so increasing the survivors base-kit speed would be detrimental to any of the M1 killers on the roster.

Blight is a different case as he is naturally a speed inclined killer due to the nature of his power being a human pinball, this means that running from loop to loop is far more dangerous than it would be against a killer with no catch up. While blight it definitely powerful you can negate his ability to hit you by running safe structures than out in the open, or even just trying to duke him (which works a surprising amount against bad blights).

What I'm trying to say is that increasing the speed of survivors would make life far easier against S tier killers like blight, it would fundamentally break the game and its already poor balance.

Honestly if you're mainly talking about all the hyper mobility killers, I can see how you feel, but the issue here is we need to take care of them. Making survivors faster would just make the rest of the killer roster feel gross to play.