I personally have a problem with playing Paladin right. The best way seems to be to rush head on with the shield to enemies, stun them, slash with the sword, repeat until everything is dead. Most of the thime you will run out of energy before you can win a long fight. So either you build everything into energy, to last longer or everything into damage, to kill faster, either way, it's a rather painful way to play and has also a high skill ceiling because you can easily mess up.
It basically stands against anything you would normally do in the game and you have constantly remind yourself to use the shield and ram the enemy.
As for the weapon itself. It's basically crap. It's a phaser gun with a lot lower fire rate and really, really easy to miss soemthing, especially on higher difficulties were everything moves so fast. Also does not help against bosses and in rooms it is very situational. The range is also crap, most walls are thick enough to cover most of the range, so enemies have to hug the wall in order to hit them.
The melee damage is better but more risky at hand. And even than the damage is more "average" than "incredibly good". The weapon might be better with some damage and/or fire rate upgrades but I have so many problems with the mech, I never got past floor 2 or3 with it (I think it was 2, were I am stuck).
Last, missile launcher. The shield is important, because the missile launcher is basically useless in blocking boss bullet patterns or big patterns in general. You can only use it in an offensive way, even in farming shards it is crap, because the explosion radius is so smal and the missiles spread out really widely.
Personally I think, this mech requires quite high skill ceiling and I'm one of the persons who thinks, if a mech is technically hard to play, he should also be rewarding. As godlike player, you should get out the most of a mech that is diffcult to play. Kinda like Penumbra and Redshift. They are basically Papermechs, even a watergun can kill them but they have awesome abalities, that make up for the difficulty. Redshift simply stops time, so all shots at you can be easily dodged unless you missstep or loose your patience. Penumbra has his invulnerability powers, that give him multiple chances to escape enemy shots.
And don't misunderstand this, Misery, but your opinion on balance is basically bullshit. You DESIGNED the bosses of the game. You know everything about them. Plus, you have TONS of experience in those games and your skills are godly. No average player can do, what you do. If you find soemthign strong, others migth not, because they don't have the same skill floor as you have. Basically you always have to rely on others in terms of balance because you know only one difficulty: Super hard. This is not meant as an offense, it's just liek it is, I don't think there is anyone here who can do the same as you.