Under Windows XP, latest build (bzr 9010): ctrl modifier does work for node type change when single clicking but doesn't for axis constraint movements of nodes in a path when in node tool (F2).
I also tried ctrl-alt click to add and remove nodes: it works. But when I remove a node between two segments (I mean straight segments of a path) I would expect the single line to remain a segment while now it's turned into a curved line. This happens both with ctrl-alt click and using delete and is different from the old behavior. It's very annoying for who, like me, usually draws only straight segments (technical drawing): I always have to reconvert the segment back to straight. Also, I can't see the point in doing in this way: if you really need this you are probably already working with curves so you don't need to do anything before removing the node; otherwise I feel it's acceptable to convert the two segments to curves before deleting the node as this behavior is not consistent with the starting shape of the path. I didn't explain it very well, I hope it's understandable. :)
Regards. Luca