Let me first make a friendly amendment that might make this idea more saleable. A summoned hero is always level 1 but there’s a chance of getting an ascended version (2nd, 3rd or 4th), with sharply decreasing odds. Putting it at level 1 still requires the player to do a lot of recruiting and farming, but it solves the ascension mats problem (in whole or in part). Some thought would need to be given about the Special level.
How could this generate revenue for SG? I draw the HotM quickly, but she’s only 1/1. Hmm, what if I keep rolling? Maybe I’ll get a better one! Buy more gems, summon more Carvers and Azars. As it stands now, I probably stop summoning.
Pokémon Go uses this to good advantage, selling more raid passes so that players have another chance to get a better example of some legendary Pokémon.
OTOH the odds of getting the HotM or a 5* event hero are already low. The odds of pulling a second example at all is poor; the odds of getting a better version even worse.
Summoning a great hero already feels great. I’m not sure it needs more happiness, or that my happiness in summoning one should be diluted with the realization that it was “only” a 1/1.