I think Companions should be broken into two types of companions:
1) Combat Companions
2) Support Companions
How about there's a third type:
3)Combo Companion- A companion that is ok in one or two support skills and ok in one type of combat (so basically a weak support companion who can defend themself)
Combat Companions are your run-of-the-mill, capable of destroying anything that sets foot upon the very Earth they scorch (okay, really they shouldn't be this powerful, but I'm joking about their strength in Fallout 3 and New Vegas), but provide little additional support. If you need a bodyguard, these are the companions for you.
Support Companions offer roles like lockpicking, hacking, healing, repairing, etc. BUT they svck in combat, and can very easily be incapacitated or killed (depending on if hardcoe mode is enabled or not).
Both types also start off at a base level of their primary skill (i.e. guns, lockpicking, science, etc.), and this can be increased by sacrificing skill books to them, rather than for yourself. This stops it from having characters choose the lockpick or science guy because he can pick or hack anything.
Also, I'd like a system like Operation: Anchorage had. You essentially have a certain amount of slots, and depending on the character you choose, they fill in a certain amount of slots. Some companions require so many slots, they're the only companion you can take (unless you choose a perk that increases the amount of companion slots you have), while others will allow to have multiple spots.
Non-essential/random NPCs that can become temporary companions should also fill in companion slots to further stop players from rushing in with a small army.
That's a good idea, how about you can have a certain amount of combat, support, and combo companions with you at a time, with there being four different companion ranks:
Weak-between 1-29 in their major skills
Light- between 30-49 in their major skills
Medium- between 50-79 in their major skills
Heavey-between 80-100 in their major skills
These include weapon skills... so you can basically have four weak, three light, two medium, or one heavey with a CHarisma of five...
Companion slots should also be affected by Charisma, since it's a pretty worthless attribute (sure it affects the base level of barter and speech, and in New Vegas also a companion's natural damage resistance, but barter and speech can easily be increased later on, and as long as you're not playing hardcoe mode, or have some pretty good armor on the companion, it doesn't really matter how much resistance they have). This means if a player has a Charisma of 1, they may only be able to take a very weak companion that only requires 1 companion slot, where as a person with a perfect companion slot could take a couple of high-powered companions, or several weaker companions.
I think that having your companion unable to die unless you're in hardcoe mode svcks... I don't want to scramble to get food and water but still have my companion able to be killed if severly beaten by a deathclaw or attacked by a couple of nightkin... in F3 it played out so well... In my first play through I first recruited Jericho, who died on my way to Tenpenny Tower, and the thing I liked about that was that once he was killed in the crossfire between two supermutants (I was a level three and one had a minigun while the other had an assault rifle) and three raider (one had a 10mm pistol, one had an assault rifle, and one had a combat shotgun), I had to dodge bullets and keep moving... In Vegas you can't leave... They're not dead just unconscious which makes you feel like you have to stand and fight instead of having the luxury of running... After a while I got Star Paladin Cross who died in Vault 87 where (right afterwards) I met Fawkes who helped me until I was kidnapped, then he helped me after I escaped Raven's Rock... So I want my folowers able to die whether I'm on hard core mode or not...