U2 tour won't exist without some sort of flashy gimmicks* IMO. Great visuals are expected since they did it on Zoo TV, Popmart, Vertigo and 360.
As for being expensive...A few screens can't be more expensive than what they have pulled off in the past. And maybe instead of focusing at least 50% of screen time on the band footage, they could be making custom-made visuals for each song. Live, during the show, improvised visuals especially if they will really dig up the rarities, as was the trend in this decade. Obviously they won't go BIG again right after 360, just go after the newest visual treats available.
*which don't really take away from the music. And they won't do more stripped down than Elevation.