Regarding alignment, I think it's not C that caused aligned reads to be the standard, but rather hardware itself. There isn't anything in C that prevents unaligned reads, is there? Aligned reads are just a consequence of storing data as vectors of a type, which is a very natural and efficient approach. Unless that's somehow a bad idea or prevents other good ideas, the point is moot.

Also caching and page boundaries have nothing to do with C. They are hardware issues (that good C programmers have to deal with, but anyway).

Contemporary Intel x86 haven't had significant problems with unaligned reads for a long time; do a web search for Lemire's post. (I guess there are still restrictions for atomic reads/writes).

I've long wanted to have access to overflow bits or traps on overflow. C certainly isn't in the way of adding them to CPUs, and signed overflow is even undefined in C, which is an opportunity to make them emit a signal or other exeptions. But I agree, C culture did not require hardware vendors to add overflow bits or traps, so maybe that is C's fault.