yeah, after he said the Second Ideal, the Stormlight started working better for him,i he gets more out of it then he did before that, he even thinks something to that effect after.
As for the other, I dunno. I think the reason Syl doesn't like the blades now is that they somehow got contaminated, maybe by all the people that used them selfishly after the Radiants left, maybe BECAUSE the Radiants abandoned their duty, maybe for some other reason. So maybe now people have to figure out how to fix it before they can be used properly again. Or figure out how to make new ones (maybe Talanel can do it?) But that's my theory.