Should RIOT give up on making new champions and focus on reworks for outdated/in need ones instead?
There is huge problem with older champions and their skillsets which are unhealthly for game itself and the gap between them & new/reworked champions expands with every released one.
Yes, I know that community is divided about this subject, some would like to see more new champions and some would like to see more reworks, but imo old champion being reworked is almost like new champion (ex. galio) so both of them'd be glad.
There are around 38 champions wich'd be good candidates for large scope changes (VGU) and at least 14 for visual update/minor art changes (ex.
, her skillset after minor gameplay update is very fine and the only thing she'd need to reach standard of new champions is just small model & animation update).
The main problem of older champions (except the art side) is their mechanic, accurately lack of counterplay and lack of skill expresion (ex. 

) thus huge gap between player's expirences derived from playing certain champion.
If you dont get what am talkin' about just compare one of the oldest supports in game -
to the newest support in game -
. Janna appears as boring and almost braindead (spam shield, use R) while rakan is pretty funny and seems skillfull to play as.
Also my advice: If you'd ask community for help (skillsets ideas, new lore pathways or design) the work'll speed up.