I’m not sure I necessarily agree with KDubya on it guaranteed being better; you get an extra action, so we can assume 2 extra attacks. If you average 10 damage per hit (discounting accuracy since it applies evenly to both sides), you need to average 5 or more attacks per short rest for the +1d8 to be better (20 damage lost, 4.5 X 5 = 22 so it’s better). If you average 20 damage per hit (a more realistic figure imho) it’s 10 attacks. 30 damage per hit (very obtainable still) and it’s 15 attacks. 40 and it’s 20, and so on.
At some point, the amount of attacks becomes unrealistic, especially if within the context of a strong party where everyone is contributing and is lethal. But it’s easy to do the math, so you can pretty easily judge for yourself which is better from a damage standpoint.
This is of course an oversimplification, the extra 3rd level spell is more smite damage, if you have an auto crit that improves the benefit of additional dice, overkill may limit that benefit, the fighting style also has an impact, and so forth. But it should give you a feel for generally which is better from a damage perspective. Far more important imho is what you would do with that feat. Something like Sentinel could result in *way* more than 2 extra attacks, same with Polearm master. And there’s no doubt Great Weapon Master is going to tip the scales if you don’t already have it by then. Given that, if you’re a great weapon user, I’d say Pally 12 with all 3 of those feats is better than Pally 10 / Fighter 2 with only 2 of them.
There are certainly pros and cons either way. And agreed, if you’re going to lose a feat multiclassing there are typically better break points, Paladin 6 / Warlock 6 for 3 attacks per round and lots of big smites sounds better to me personally than Pally 10 / Fighter 2 for example.
