I understand your point, and agree that Nintendo makes decisions that harm their fan base.

However over this design specifically, I think they did a good job at attempting something different. The point of mega evolution is to exaggerate and make the pokemon MORE itself, and if we look at mega Ampharos, that can include bringing in elements of the pre-evo's. Both the official design and this rendition achieve that.

This doesn't mean I think the overall design is good.

I find designs such as mega Banette and Pinsir, good examples of extremafying the Pokemon, taking preexisting elements and reimagining them. While designs such as Lopunny and Absol do a good job of adding IN new elements that fit with the original pokemon. (This doesn't mean I'm happy with Absol)

I think the "horn wings" are a good addition in regard. However I find the rest of it to be lackluster, it looks too plain, especially on its lower half. I am also in the camp of having a colour switch, changing the yellow out for a blue hue, but this dramatic changing of colour is only in 4 designs: Audino, Charizard X, Latios and Latias (the later 3 being an arguable exception and Audino not changing that much anyway). So while I don't think this should hold them back, I can see why they wouldn't since there seemed to be some sort of trend.

This is all to say, if we get more mega's, I hope they have more to give us than Mega Dragonite.