It's been a while since we last had a menu update so a new loading screen Graphic would be nice. The problem/question is who spends time working on these kind of things (and why). There's a lot of work that people have asked for to improve the game itself. Another team is working on the new client, implementing an almost endless list of features (as well as fixing many that keep breaking with every patch). It takes weeks to develop and create this content. That is weeks of hours spent on something fairly menial and pointless.
To go down this animators specific example, they split the backgrounds and the characters in each loading sprite to then give each of them basic animations (see the source content). This animation exists for all the champs and the high-end skins that made it with their own login screen, but the rest would be static images. This stands against the most basic of design philosophies; inconsistency is bad.
To ignore the question of IF it should happen and instead focusing on how I would change it, I would start by avoiding slanted portraits for each Champion, as the example is far too similar to LoL's largest competition: DotA. If I were to decide how to revamp the model, I would place player images of curtains inside grid slots, to then open up to the champion upon their loading to 100%: Example. This'd allow for interesting animated screens, more focus on skins (the models would be animated unlike by quick rendition) and a more interesting wall.
Turning back to negativity though, adding models or other animated intros would only increase the work PCs need to do before you get into the game. It would increase the loading times of players (as well as possibly need a 5s countdown from when the last player is ready). Riot's goal for quite some time has been to shorten the time between hitting play and standing in lane fighting, not lengthen it. This would be a nice overhall graphically speaking, but maybe not as productive for the game as Riot desire. Certainly not worth the timely investment to make it all work.
Final Note: You're not the first person to make this exact suggestion on the board, and I doubt you'll be the last either. Either way, please reference the source when you go take others work to make your point...
