Yeah. I honestly don't know if this can be balanced, but if it is it has to be done carefully.
I think the main change I'd make is that once down you can't upgrade them. You sacrifice the Level 3 sentry completely, in exchange for two level 1s. And if using the wrangler you swap between them with Mouse2 rather than controlling both.
2x Level 1 | Level 3 | |
---|---|---|
bullet dps | 142 | 119 |
rockets | no | yes |
health | 300 | 216 |
metal cost | 260 | 530 |
Seems like its still quite weighted towards having two level 1s, so we probably need a couple of extra adjustments. As a first pass maybe try something like:
200 metal cost each
-20% sentry health
-30% sentry build speed
Its not ideal and there is an element of "if you have to add so many negative modifiers to make it balanced it probably isn't a good idea in the first place", but I think that's a good place to go into gametesting with (and you'll absolutely need the gametesting to get it right).
And maybe it doesn't really work in that but I'd like to see it in-game before passing judgement.