Dimitri will wear his glasses every now and then, no worries (to the megane fans haha). He's so sweet and adorable though, so precious. People who are turned off by the plot of dating the brother of your ex are missing out! Dimitri is perfect boyfriend material :D
If you like Dimitri the most, and also enjoy Neil, your next type would probably be Caine (he's a more childish version of Neil), and then Aiden (who is hilarious and suffers from social anxiety). All of them will have their adorable moments though!
Bullying Neil is way too much fun to not pick those options whenever I play-test the game >_> besides, it leads to an ending where he's the one who gets all super flustered! Mwuahaha, finally we can torment the tsunderes.
Psst, your best CG will probably be another Dimitri CG, involving a cat. And sleepiness. And glasses.