Yeah, with SD betas are more like what most people would see solely during an internal testing stage. You can expect a Lot to change by the retail release. If you're expecting the game to reflect the fun of the finished product atm, it won't. The current Beta 3-A doesn't include tactical battles, constantly crashes, the tech trees and magic are being completely redone etc. I find it a fun and exciting beta process but yeah, as above posters mentioned, don't expect a "traditional" beta.
If you're "looking to be convinced" I'm pretty sure the beta process wouldn't be appropriate. Not a poor reflection on the game by any means, just a reflection on the amount of work still being done before release.