I find Mega Latias/Latios to be the ugliest. It is my least favorite mega form.
Latias is my favorite Pokemon. I really like Latios, too. I like these features of the eon twins:
- the design of their arms and how they would tuck them in when flying around at a jet-plane speed.
- the design of their wings
- the design of their interesting tail/end, especially how Latias's is tame compared to Latios's spiky end
- the design of their ears in how Latias's ears pointed downwards and Latios's ears pointed forward, again, signifying their personality. Latios is more aggressive than his sister in Pokemon Heroes.
- triangle being on their chest, plus it was the color of the other sibling
What I don't like about their mega forms:
- the design of their godawful arms. Their arms are not that long and it doesn't make sense. How can they tuck their arms in backwards, anyway? Think about it. In their original forms, they tuck their arms in with their claws facing the front. This is easy enough for you and I to do. In their mega forms, they are tucking their arms in with claws facing behind them in order for their "wing" to face the correct direction. Can you tuck your arms in like that without your elbow being in the way? wtf. I don't understand it nor do I know what the designer was aiming for when giving them these kind of arms. Even in the Soar feature they only tuck in their arms in whatever way (collapse, break a bone, I don't know) when doing a Boost. So, frankly, their fattened mega form is actually increasing the air drag or air resistance. I am mega displeased, that's what.
- the wings are completely different and are attached to the arm in a most unflattering way.
- the design of their lackluster tail fin that also took away the differences in their personality
- the ears were really not changed, but the added spike on their cheek is pointless and unnecessary.
- triangles are plain white and the placement on their body isn't as inspiring as it being placed on their heart.
TL;DR everything I loved about the eon twins was butchered in the mega form design