1 - Do you think CO would ever Hub at DIA again?
Possibly - but I'd guess such an event would only come about through M&A's.

2 - Would you fly CO in/out of DIA?
Trick question -- Colorado and I do not mix so I find my potential travel options there limited...but that's just me.

On a more serious note UA has launched very aggressive marketing campaings to retain the grip on DEN and I suspect they will continue to do so in order to protect their market share there.

Again if there's a M&A event than the game changes.

3 - Do you feel that this would be western enough to be built out as a hub for CO again?I don't know enough about the O/D of DEN to comment on 'hubability' but DEN seems to do well for UA and I would suspect the catchment area of DEN is impressive too.

As for a connecting hub...not sure. Maybe for regional markets but I would think DEN to be too far east to be a player on North/South West Coast traffic.

4 - Potential benefits of a CO Hub at DIA?
The ability to capture a market with a presumably large amount of O/D/

5 - Potential negatives of a CO Hub at DIA?
Weather.

Also I would think CO would be better to focus their resources else where than building up another CLE (not that there's anything wrong with CLE!). What I mean by this is for CO to build a hub just for the sake of connecting domestic traffic through it seems like an expensive proposal -- especially when they already have IAH and CLE to help with this.

Should Larry & Co. wake up one morning and decide to build up a hub somewhere I'd think it would take more than just the possibility of connecting domestic traffic. I'd guess you'd need a strong mix of O/D, international and prime location to make it work...and while DEN by all means might have all that...one wonders are they any other potential cities out there who fit the bill better?