Paying back a signing bonus if they fire you seems super rough. Is this common elsewhere? 2 years also seems high - the time I got a signing bonus, it was "pay back if you leave voluntarily in 1 year" which was much nicer than the described.
Unfortunately, much of this seems pretty common, especially months-of-crunch-time. Being able to figure out projects to avoid (if you're at a big corp like this where such things are possible), and being able to avoid them is a very good career skill to cultivate.
On-call can work quite well if the team has sufficient ownership to improve the underlying issues, not just keep the lights on. I've done this with good success. I'm often disappointed by how many managers and companies I've seen who don't get that aspect.
Believing too much in mantras like "adding manpower to a late software project makes it later" can be dangerous, too, though. How well it works depends on the manager and the person scoping and planning the work. Another critical skill to develop to escape being the person doing the grunt work.