We don't need to hypothesize as Wirth and Hansen took the path of subsetting and improving ALGOL instead of BCPL. We get to see the result. :) The C alternative would've been a subset of ALGOL like Modula-2 or something. Gradually-improving type-safety, memory-safety by default, option to remove checks for performance, modules, less undef behavior, better linking, easier analysis for optimization, and quicker compile/test cycles. Having coded performance-sensitive applications in languages like that and C tells me the level of complaining would be much lower if it's in any way tied to number of vulnerabilities, time spent debugging, or ease of modifying legacy systems without major breaks.

It's also not hypothetical: all kinds of developers use such languages. C is the exception to the rule these days. Even in UNIX & C's domains, there's new comers kicking the crap out of it in terms of balancing development speed, production speed, safety, and extensibility. Redox in Rust comes to mind given the OS and language attempt a Right Thing approach to bootstrapping an OS with small team. Progress has been impressive.