In fairness I remember Serena and Clemont being used in a LOT of action situations, just in a far less developed manner than Ash, they always got the jobber villains while Ash got the more formidable battles (even against Team Rocket Ash could sometimes sell them being threats and make things interesting, while the other two had to always get the curb stomps), and while Ash could sometimes put himself in the thick of things in some eventful way, Serena was plot armoured (there's only so many times dancing can work as a chekhov's skill against bad guys
) and Clemont just had his deus ex machina gadgets.
If anything I could argue the problem there was overusing these characters for battles when it wasn't really their niche, having battles inflict their development when they couldn't make it interesting (Clemont had the odd good battle but he was more the science guy). It looked like they wanted to diverse the XY cast but they were still slaves to the formula. I actually like that SM is playing more with the idea that battling doesn't have to be the be-all-end-all point of training and having situations other strategies come in handy, which makes things less repetitive and the characters more diverse.
The bigger problem is that for the most part, it's STILL the battlers that are getting the more versatile roles. Ash and Kiawe stopped Buzzwole with a non-battling strategy, while Ash is more liable to partake in strange methods like being host for the Morelull or playing Passimianball. Sophocles and Lillie have had the odd good role due to being the brains of the team, but in terms of agenda and abilities, a lot of them feel very under-utilised, even without battling. Mallow hasn't got to do ANYTHING with Steenee besides beat up Team Rocket a couple times, and it really doesn't feel like it has to be that way.
(I just know I'm going to get an infraction and banned for talking smack about XY again despite the fact I didn't even bring it up so don't be surprised if I'm gone for a while.
)