@gemspender To me, this would generally not be worth the full cost of food to get 3 dragons to level 40 (I think this is about 50 to 60 million if all dragons start at level 1) as well as the amount of gems to speed up empowering 3 dragons to 1 star (about 150). But I think there are some exceptions in which it would make sense to complete heroic quest 2:
The heroic and/or legendary dragons involved seem particularly useful for arena/league combat. I think a lot of players made this case for high ethereal, given its wind defense and (at least current) inability to be critical hit.
A player already had one or more of the dragons at a decent level, and possibly already empowered. For example, if there was a “high positivity” heroic quest, a fair number of folks already have the high pos and space knight at level 40, and plenty of players have space knight at 1 or more stars (plus everyone who used the nyxonite on high pos already has him at 4 stars). I am guessing most players do not have an empowered level 40 colorful dragon, but if one only needs to feed and empower colorful, the cost is manageable.
A player has a large surplus of food and gems - probably relatively less likely, but if this is the case then why not?
BTW - I forgot to state this earlier, but the quests can be completed in time without speeding up stages, assuming one starts quest 2 soon enough. Empowering all 3 dragons can definitely not be accomplished during the event without gems, however. If the dragons are already empowered, then no gems would be required at all for these quests.