Battleship

I don't get it. What's wrong with Band of Thieves. It betters with progression.

Level 18: MP -30; Basic attack 180%, 3 "other selves" will attack enemies
Level 19: MP -40; Basic attack 140%, 4 "other selves" will attack enemies

You tell me which is better, 4 target mob skill for 720% damage total or a 5 target mob skill for 700% damage total (assuming you hit 5 mobs, which happens less often than hitting 4. It happens at other skill levels, but level 18-19 is the worst deal ever.

Level 18: MP -30; Basic attack 180%, 3 "other selves" will attack enemies
Level 19: MP -40; Basic attack 140%, 4 "other selves" will attack enemies

Level 30: MP -50; Basic attack 210%, 5 "other selves" will attack enemies

You'd still be better off maxing the skill. It's not like battleship, which doesn't get better at Lv 10. For example, if at level 9, suddenly you get 45 sec cooldown and the cooldown disappears at level 10, then you can say that it betters with progression, but that's not the case here, so I don't get what you're trying to point out. If the max level or near max level is the best, then it levels with progression. You can say "well, Elemental Amplification for mages has discrepancies in the MP useage which makes one level worse than the next", but then you'd still max it, whereas with the battleship you would not.

Same with Spear Crusher when you move from

Level 15: MP -16; Basic attack 120%, attack 3 enemy 2 times
Level 16: MP -19; Basic attack 124%, attack 1 enemy 3 times.

Yes, but eventually, the skill at Level 21 will = the Level 15 Crusher, then will hit even more targets at Level 26, so it betters with progression.

Yes, again, the maxed level is what you're better off getting.

Battleship doesn't hit certain levels that are better to skip, though. It appears that it simply gets worse.

Exactly. So instead of pointing out flaws within maxing a skill, why don't you point out ones that simply gets worse?