Yes, I agree that 17...Rag8 is rather cooperative, but all the same I would say that the position after 16...Qd5 is just a little bit better for white, as the black king is a little shaky and his pawn structure slightly weakened. White can try various moves, for example 17. Qc2, 17. Re3, 17. Qe2 or indeed Gutman's 17. Qe1 and after your improvement 17...Kf8 18. Ne4.
I also agree that 11...Kxe7 should be replaced by 11...Qxe7. After 11. Nxd4 however, I think 12...0-0-0 is less good on account of 13. Nxc6 bxc6 14. Qf3 Qd7 15. Nc3. This was already given as clearly better for white by Schlechter somewhere around 1900, so I'm a bit confused about Herbrechtsmeier's recommending it.
Better is 12...Rd8. After 13. c3 Nxd4 14. cxd4 Rxg7 15. Nc3 Gutman gives 15...Qg5 16. Qf3 c6 17. Ne4 Qe7 18. Qh5 Kf8 19. Qh6 with a clear advantage to white, but again this variation is a bit cooperative. Much better is the solid 15...Kf8 with white having reached next to nothing.
So, just when I thought it was time to return to the good old Ruy again, I noticed that ...Qxe7 is less good when white changes his moveorder to 8. fxg7! Rg8 9. Bg5! Be7 10. Bxe7 Qxe7 11. Nxd4! Here Gutman thinks black is ok after 11...Be6 12. Nxc6 bxc6 13. Nc3 Qf6, but after 14. f4 I think this is definitely not the case!
For the moment I still don't see black reaching clear equality in the Max, unless there is a mistake in my analysis of course