I really do think both teams lookk better although the Bucks have a thin bench but could go 9 deep w/o playing Markota, Hodge or Grier much. plus add Simmons to that next season and we would compete to have the best starting 5 in the league
We don't need Gasol to make the playoffs. We would have made them easily this year if we just stayed healthy. We'll make the playoffs easily next year as well, as long as we stay slightly smart this summer, and add two more adequate defenders (one through the draft, and one with a small MLE type contract).
Also your dream lineup of Billups/Redd/Simmons/Gasol/Bogut would be pretty great in the east, but still not the favorite for the championship I think. Tough to say, and it would be an ENORMOUS gamble to take, considering how much money it would take to steal Billups. That would be three max contracts, plus Simmons who isn't exactly cheap. Luxury tax for sure.
EDIT: Come to think of it, I don't know if I think signing Billups in that scenario is even technically possible. I doubt it is.