Yes he is a patriot, but he also asked others to step down so that a strong true conservative might be able to take down the front runner. I don't see that as very humble. IMHO Walker got it wrong in placing blame. He needs to understand that voters don't want anyone associated with the establishment. They no longer trust the establishment and rightfully so. The GOP establishment has failed the voters and it is the failure of the GOP establishment that has divided the party. The only ones holding back a true conservative are the GOPe candidates like Bush, Christie, Kasich and Graham. If they were out of the race, I think that there is a strong possibility that Walker would still be in.
I'm not sure why you see stepping down to allow a smaller conservative field to take over the front runner status from non-Conservative, Progressive Trump is not humble, but I certainly do.
As for the 'establishment,' Walker himself is not part of it, and there are other conservatives in the field who have fought the establishment (your guy, Cruz, for one). Bobby Jindal is strongly conservative and is still in the race, and certainly doesn't qualify as a dreaded GOPe either. Fiorina and Carson are both non-establishment, and both more conservative than Trump by a long shot.
I think Walker was seeking God for guidance, and I think he found it. I have nothing but respect for the man.