I have a few suggestions I want to make after toying around yesterday with a dev version of MPS.
there's been quite a few posts, so I don't know if things have been suggested before or not, but I'll post them anyways.
do note, I have no coding knowledge, so I am just shooting some suggestions around.
one suggestion is about the new option to customize your model completely with colored parts, where you can leave things in and out. it's really awesome, especially since you can preview the power armor, rotate the image and even zoom in.
but not everyone is creative, or are good at customizing things, but still want to have an awesome looking armor. but it'll be really messy to share those configurations like that. so would it be possible to customize your armor, and save it as a profile, and have each profile be written to a file that people can share with eachother? so that people can download the profile files and move them into their minecraft folder, and can select those profiles ingame. this would also be really nice if you for example are playing in several worlds, and don't want to constantly manually configure your armor in each world.
another suggestion, which is a small one, involves a HUD, which already is mentioned on your website. it'd be to move the power bar, that you see now, to a HUD module, instead of showing it by default. the module wouldn't be that expensive, since it'd only show the power bar, but you can customize a few options like the looks of the power bar, and the location of it. now this suggestion is probably useless, since you probably already have ideas and plans for a HUD module and for the power bar, but I still thought of sharing it. but if you ever get to adding the hud, you might also want to consider adding some sound effects to the module, somewhat like jarvis in Iron Man. it could just be some random sound messages, or have sound messages actually linked to certain functions.
a suggestion I also have is about maybe sort of a new weapon, or an option to the flight control module. it'd be a way of quickly descending from the sky, and if you go full speed to the ground, you cause an explosion around you, maybe have it somewhat like a meteor boots module, where you can set the power and explosion, so that for example it'd only hurt entities, or actually cause an explosion. it's not a module that's that useful, but it'd be handy if you've a group of mobs that you quickly want to take out while you come flying down. another weapon module would be a grenade module, where you can throw grenades. basically it's like the dynamite from IC2, where you can choose your throwing distance by how long you hold your right mouse button.
and a small addition to the plasma cannon could be when you aim it at full charge into wait, some fish might get dropped as loot.
I also have a suggestion for the tinkering table, it'd be nice if you could have a summary page where you can read information about your whole suit, like how much power it has in total, how much weight you have in total, and more information like that. something I know that's already been suggested before is to have the option to have several configurations of your suit on hotkeys, so you can change your configurations for the situations you're in. it'd really be nice to just change your suit configurations with a single button, then pressing several buttons or having to open the hotkey GUI to move modules around. these configurations could then also be controlled in this information page, where you can add and delete configurations. I know there's now a module you can add to your power tool so you can have a tinkering tool, but it'd still be quite alot of work to constantly change your settings. now to balance this a bit you could make it so each configuration needs to be written to a disk that you need to craft, and by deleting a configuration you can get that disk back.
a cheap module for people who just started out could be a grapling module on their power tool. they could then shoot a grapling hook towards a wall, and they pull themselves towards the grapling hook. it could have an animation of the claw of the power tool actually shooting with a rope on it, and when you right click you get pulled towards the grapling. this could also be useful to cross over holes if you don't want to build or walk around it. it can also be used in reverse by you being able to pull entities towards you. so it's somewhat like the fishing rod.
these are just some ideas I came up with, and you can disregard them as you like.