I totally agree. In these two specific cases, R53 + ELB wasn't going to work for us though, because of reasons. (I don't think I can go into specifics, but they're actual reasons.) Our workaround was reloading the configs (which triggers a DNS cache flush on both Nginx[1] and HAproxy[2]) once every couple of minutes.

I know, I know, I hate it too. We're working on it. Just wanted to share the workaround.

[1] http://wiki.nginx.org/CommandLine#Loading_a_New_Configuratio...

[2] http://www.mgoff.in/2010/04/18/haproxy-reloading-your-config...