I live in Denver and I loved the Crush, but I am pretty skeptical that a team could succeed here without Stan Kroenke's involvement (the original Crush were co-owned by John Elway, former Denver Broncos owner Pat Bowlen, and Stan Kroenke himself).
There aren't very many arenas in the Denver area capable of seating decent crowds.
Ball Arena - the main arena in town, owned by the Kroenke family and home to the NBA's Denver Nuggets, NHL's Colorado Avalanche, and NLL's Colorado Mammoth (all three also owned by Kroenke)
Denver Coliseum - gigantic craphole. Construction began in the 1940s, it was considered decrepit and outdated in the 1970s when it was replaced by McNichols Arena, and McNichols itself was demolished over 20 years ago for being outdated. Horrible building with horrible bathrooms and concessions, bad parking situation, bad neighborhood, nobody wants to go there for any reason.
Magness Arena - home arena of the Univesity of Denver hockey and basketball programs. It's a really nice little building but the University has never rented it to anyone else and DU sports prices tend to be really high, rivalling NHL and NBA games.
1st Bank Center - not actually in Denver but in the suburb of Broomfield. Also controlled by the Kroenkes. Too far out of the way. We've already seen a CHL team and an NBA D-League team go belly up there. EDIT: This arena is actually scheduled to be demolished, so cross that one off the list.
Bottom lines are:
1. An AFL team is likely going to need access to parking and concessions revenue to succeed. The only situation where they're going to get that is if they play at a Kroenke building with Kroenke ownership.
and
2. Denver is a major league town. The Crush were popular here because they were presented as a cousin franchise of the Broncos, Nuggets, Avalanche, Rapids, and Mammoth and they had John Elway's face and Pat Bowlen's 2 Super Bowl rings worth of goodwill backing them. They played in the big league arena and drew big league crowds. Denver fans have the NFL, MLB, NBA, NHL, MLS, and NLL plus several major college sports programs in the general area. We're not going to spend money to watch minor league sports in a minor league barn.