In the case of illuminted reticles, my question is, does the increased size of the reticle on low power in low light have a blinding or washing out effect?
It is true the reticle getting larger increases the amount of light, but this hasn't been a problem with the FFP illuminated scopes I've owned (Premier, S&B).
On high power there's an illuminated cross in the center and on low power it pretty much just looks like a dot. However, it's not a problem the way you describe because the illumination systems are good enough that on the lowest setting they're so dim you can barely see them even in complete darkness so washing out is not a problem. You just typically set it a couple notches lower on high power than you do on low power.
That may not be true with all brands though. For example the NF F1 where the entire reticle illuminates and you can't easily adjust the brightness in the field might not work as well as the above and may suffer from the washing out you describe. I don't know that's the case though--maybe if somebody here owns one they could comment.
I've got a couple Vortex PST's on order (a 4-16 and 6-24) so it will be interesting to see how well they work. They illuminate more than a small center cross that the Premier and S&B do, but they still only illuminate the thin center lines. And of course the intensity is adjustable so I'll just have to see how dim they are at their dimmest. I'll let you know when they get here.
As far as FFP vs. SFP for hunting to the OP, I'm pretty sure we already have pages and pages of discussion covering it and that's a lot to retype. Go back and read those threads.
The short version of my opinion is that if you're actually going to use the reticle for anything in the field, FFP makes life so much simpler. I simply find no reason I'd want a SFP other than cost--and hopefully scopes like the PST are going to make that less and less of an issue.