I run a 16" 215/55/16 on 7.5" wide wheels and the ABS is not affected to my knowledge (it still works is all I can tell you). I actually ran a 225/50/16 for a short while and they didn't affect it either but they did rub on the back right (after lowering) so they came off quickly.
I find the ABS doesn't kick in as often now I have all the upgrades that I have and I can say I have never lost adhesion when braking hard. I have yet to upgrade the disks and pads. Wider tires do tend to tram-line more so if you do go larger in width just keep that in mind.
I enjoy the wider tire and use a Summer only tire when weather appropriate: Kumho Ecsta SPT as seen
here. I have to agree with the ratings for dry and wet (these were my main criteria, especially the wet performance).
I run a 15" wheel with 196/65/15 in the cold months.
I found that ride comfort was affected not by the width of the tire but by the depth of the sidewall. A shallow sidewall increased the 'level of discomfort' shall we say.
This calculator will help you pick the correct size if you do decide to change to a 16" wheel and tire.
I would definitely recommend having a winter and summer setup unless you live somewhere that doesn't get snow. Not everybody does this but in my experience a good Dunlop M3 for the cold weather and a sticky summer tire makes driving safer and more fun.
I hope this helps.