I worked in software development for about ten years before getting thoroughly sick of it.
The best way to slow down a software project is to add people to the team.
Which is not to say that giving Toady a bunch of money might not help. He could build a lab with five rocking development machines in it. He could hire an assistant to handle extraneous, non-programming tasks - although, depending on his management skills, that could also throw a wrench into his productivity. He could order takeout every night instead of wasting his valuable time boiling water for mac and cheese. Etc.
But adding new programmers to an existing project is death. And not the fun kind of dwarfy death with spikes and poisoned pus and goblins.
Wha?
Any big project has people leaving and new people joining all the time. If it's death to add new programmers, than practically no big projects would ever get finished.
If your projects are slowing down when you add good people, then you can blame it on crappy managers. Of course, initially there is a period of adjustment where new people have to get up to speed. Some of the current staff might take a productivity hit because they have to help train or something. But usually, big projects and managers have an established process in place to handle new people.
No way that anyone could convince me that adding a top tier programming staff to DF wouldn't provide a big kick and boost to the game. The only issue is Toady himself and whether he wants the help.
The reality of today's world is that no one can be good at everything. It's just too complex. That's why you get specialists. Right now, Toady is trying to do everything, which means that he's had to make a lot of compromises.