Exp share is only ok if the game is balanced around it. If using the exp share leaves you around the same level as the champion then it's fine. If it's bullshit like BDSP where the original game clearly wasn't balanced around it then it ends up a broken mess.

You don't *need* to grind but a well designed game will make it not so much of a pain in the ass. Johto is a big example of what not to do. Extremely limited exp, rematches are a bitch and a half to do., horrendous level curve etc. Unova did it really well.

However, playing and beating the game without grinding and being under leveled is extremely rewarding. Of course if you want to be 2/3 levels under the champ at most or even equal to them that's fine too