Lucas feels incomplete and rushed as DLC for a couple of reasons and deserves more polish.
1) Reuses more animations of Ness even though he had his own unique animations in Brawl. (Final Smash and item idle animation)
2) He has Unused References to Custom Moves (Explained more in detail here, discovered by me), which is structured like the other non-dlc fighters including an unused 4th custom move Which data can be loaded if you try modding the moveset files.
3) Some tips aren't accurate since launch and most likely are supposed to work like Brawl's version of his Up-Smash which is the 5th Strongest in the game not the strongest and cannot attack opponents under the stage on most of the cast.
4) He has an unused fair hitbox (Discovered by me)
On the OpenSa wiki (which documents data of the Smash Bros. Series, mostly Brawl though) it makes me question whether or not he was developed before Mewtwo since his VC and SFX Bank are ordered with the non-dlc fighters. (Before Olimar's soundbank and after Diddy's soundbank)
So far there's polish seen in Lucas, though there's still more information for him to be discovered in the future.