One of the things I've seen people consistently screw up in rewrites is perf.
I was in the unfortunate seat more than a decade ago of having MY code up for rewriting. It worked just fine, but people argued that I was the only one who could work on it (not true, but it could have been cleaner, no doubt).
Anyways a small team dedicated six months to rewriting my server code. Six months later they scrapped the rewrite. It ran at something like 20% my sustained throughput. I used to joke that their code was, "copies all the way down". And sure my code made a lot of use inline asm and some nasty tricks, but it flew.
Would I write it the same way again, probably not. But when you're doing a rewrite people have something to compare you against.
I was in the unfortunate seat more than a decade ago of having MY code up for rewriting. It worked just fine, but people argued that I was the only one who could work on it (not true, but it could have been cleaner, no doubt).
Anyways a small team dedicated six months to rewriting my server code. Six months later they scrapped the rewrite. It ran at something like 20% my sustained throughput. I used to joke that their code was, "copies all the way down". And sure my code made a lot of use inline asm and some nasty tricks, but it flew.
Would I write it the same way again, probably not. But when you're doing a rewrite people have something to compare you against.