Int it´s the most difficult stat to raise, yes, and also in the long run I believe that it´s a superior option. But having a low Int it´s not a game breaker at all. In the first stages of the game have very few influence, while having a high ranged combat or a high melee combat, or a high gambling can have a strong influence from minute zero. And also, depending of your play stile can have more influence or less. It´s not the same if you are going to play an academic character or if you are going to play a combat oriented character. Or a hunter. Or a gambler. Or an artisan
Think of it as along term investment. If you want to play in a min-max way, yes, intelligence it´s the best option. But if you want to play in a role playing way, choose whatever fits you best. And you can perfectly have a fun, successful run with a low-med Int character.
Also, there are some repeatable events that raise your intelligence. Few and hard to get, but they exist. Not very familiar with them, but IIRR playing video games have a small chance of raise your INT
