Class based banner

Honestly your lineup is pretty decent already with the lack of sabers who could stand up on their own offensively, single target archers, and the extra class of course.
Now about the class based banners. Just my opinion though. All of it the class banners has 2 or worse 3 five stars in it so aiming for a single one would be really hard and would require extreme luck so...it's not really recommended unless if you're just aiming for the three stars and stuff or probably more four star servants, but they all share the rate up, so good luck with your just separated into class story gacha.
Honestly it's always better to aim for the rate ups of a few servants, so...just wait for Musashi in my opinion AKA class based is just a bait banner placed by DW to get rid of your wallet just like the sigularity ones, but is good when you need certain classes.

I'll say saber, since all your sabers are niche. Also your other classes are pretty set.

Your weakest classes are:

- Saber: D'Eon is a tank, it's preferable to have a DPS too; Siegfried is extremely niche; Nero is in general just kinda average. She has good durability and good buffs (though RNG-reliant), doesn't really stand out as 'good'.

- Rider: Mordred: can spam NP but only in the right team setup, generally very low damage; Astolfo: good for trap memes and not much else tbh; Anne & Mary: Very gimmicky, strong burst damage but inherently risky to use; Marie: Kinda okay as support, that's about it.

- Extra: obvious

I'd say save for Musashi since you need a good saber and she is one of the best. If you are going to roll the class banner instead, go for rider or saber