5th Edition Reworked for Sci-Fi Game

[Fairfieldfencer]

So, I'm planning to have a Mass Effect themed D&D game with some friends next year. I wanted to make the rules of D&D match up a bit better with the play style of Mass Effect and this is what I've come up with so far. I was just wondering about people's opinions and if there are any obvious flaws so far.

WHAT I'VE GOT SO FAR

50 Health Points

50-75 Shield Points

Shields recharge to full on a turn when the character has received no damage whatsoever. Health only regenerates to full from Medi-Gel.

All armours have base ACs. Dexterity does not increase their AC.

AC is now the armour's base AC eg 10, plus the number of squares of distance. For example, an enemy with a base AC of 10 standing 5 spaces away has an AC of 15 (bring a ruler). AC is increased by +2 when shooting from cover. AC is increased by +5 when completely in cover. Taking cover is a bonus action.

Accuracy is a new ability. The modifier for it contributes to Attack Rolls.

All classes with biotic abilities lose 5 Shield Points when using a biotic attack.

All Special Abilities (replacing spell slots) recharge similar to a dragon's breath attack. The more powerful an attack, the higher the dice you have to roll. EG Rolling 3-4 with a d4 for a Biotic Orb and 11-12 with a d12 for Stasis.

[Calen]

Depending on your intended CR for enemies 100+ health is insanely high.

With your shield mechanic you could easily have health go up by Con Mod each level and have shields go up by Int Mod each level. If you are worried about dangerous attacks throw in a Shield Gate Rule. (An attack can't damage both shields and health of a single target. Any damage that would exceed what the shields can take is lost.)

[Fairfieldfencer]

Well this game is intended to be a one-time thing and I went in with the idea shields go up instead of health. I'll reduce it to 25 health.

[Vogie]

Instead of replacing Spell slots, just refluff them as technology that has to recharge & reload over time... which happens to be equivalent to a short or long rest. No need to roll for it, just plug the sucker in.