I'm not familiar with 5th ed. of DD. I played the 3rd ed. based games years ago like BG 1 & 2, Ivewind Dale 1 & 2, Neverwinter Nights 1 & 2. So is a Battlemaster Fighter so much better than the Eldritch Knight? I chose the latter in my current playthrough of BG 3. I just thought being able to cast some spells, can't hurt. Seems like I was wrong, since Battlemaster fighters seem to be much more common.
Battlemaster and Eldritch Knight are both great options in tabletop 5e, roughly equal in strength. However, there's a few things in BG3 that make Battlemaster the superior option.
- The Frightened condition caused by Menacing Strike is supposed to only cause disadvantage on the enemy's attacks and prevent them from moving closer to the source of their fear. Larian has changed this to force the enemy to run away (provoking opportunity attacks) and they lose their entire turn. This changes Menacing Strike from a fairly useful debuffing ability into an OP fight-winner, especially against solo powerful enemies.
- In BG3 every class can use scrolls, so why would you play a Eldritch Knight when you can instead play a Battlemaster and get all the benefits of the EK subclass via scrolls?
- BG3 hasn't implemented some of the spells that make EK so good in tabletop, specifically the cantrips Booming Blade and Green Flame Blade (spells that add damage/effects to a melee attack) and the 1st-level reaction spells Absorb Elements and Shield.