Pokemon. The last entry (sword/shield) were IMO the easiest the franchise has ever been. Theres was hardly any challenging battle, there was hardly any battles at all, I think its the game with the least trainer fights in it And the lack a bigger pokedex and focus on competitive game doesnt help it either. The franchise has been the exact same down to dissapointing endgame content, makes the series feel stagnant. A return to form with more dificulty spikes and perhaps different gameplay mechanics and interaction with the overworld would do wonders to this series. Maybe even go open world with it, like so many fans fantasized about when they first announced it was coming to Switch. This is obviously something that'd be my personal "wishlist", the series is selling fantastically well as it is and I doubt execs would think it needs a revamp.

Suikoden. The "different direction" being not staying dead. Revive the series. 

Pokemon is an easy choice.

My passionate choice is Star Ocean. Star Ocean 5 was "look! look! Star Ocean 3! Seeeeeee! Please forgive us". Star Ocean 5 did nothing to advance the series forward, it is actually a step backwards in every single way possible. On top of that Star Ocean has nearly the same set up every game - How many times is someone gonna get stranded on a planet to learn that the planet is in some kind of crisis then to find out that crisis is caused by one of Pangalatic Federations many enemies, THEN to find out that somebody in the party is a undercover Pangalatic federation agent investing it closer? Been there done that do something different.

Syphon Filter, change from the direction of not getting any release =p

Now on a serious note, I think that the series I really like either have already changed (and perhaps should change back) or are fine the way they are.

Final Fantasy should try the radical approach of being a turn based RPG where you control a party of characters.  They should focus on telling an epic story with relatable characters.  They should be willing to sacrifice a bit on graphical fidelity if it means making the other parts of the game better and having a decent release window.

Sounds like Bravely Default.

I'd like to see a Halo adventure or western RPG-type of game. I wouldn't want them to abandon their regular linear shooter formula for that though.

An open world shooter along the lines of Destiny would be cool too. In that case, it would need to be a shift for the core of the series.

Tokyo mirage sessions.

I'd like a proper cross over please. While I do like my waifus and music, my expectations was very different when they told me SMT x FE was happening vs what we got

The Secret of Mana world has always irked me. I love Secret of Mana, but every single game after has just used the aesthetic, but not the gameplay or even the world really. I'd probably say the same for Final Fantasy since X, although I did enjoy XII for what it was.

For the most part, though, I really enjoy the risks developers take with their IPs, particularly Nintendo. At the end of the day, it isn't the concept oftentimes that makes or breaks games, it's the execution of those ideas. I could imagine a million ways that Metroid Prime would have been a terrible game, but with the right guidance and the right amount of polish and dedication to world building even turning a 2D sidescroller into a First Person Shooter (Adventure) can work.

Danganronpa.

A game with so much potential wasted by a terrible linear plot. Sometimes I wish to see how this series would work if made in Telltale style.

Well, anything would work better than the canon route anyway.

I wouldn't want to see the FPS Halo games disappear or anything but I would like to see 343 make an RPG Halo (maybe in the vein of Mass Effect?)