Currently, Nexus guardians are extremely under-utilised, and for good reason. They have few abilities, they're weak, and they're hard to control; in short, a far cry from the "effective and deadly support" mentioned in their help-file. After using one for a while for testing, I compiled a list of suggestions for improvements, but feel free to comment on the suggestions or make your own to see if they can be enhanced to a state where they're actually useful.

• GUARD LOOK - Should be able to be used off-balance. It doesn't consume balance as it is, so it wouldn't actually harm anything.
• GUARD STATUS - Should be able to be used off-balance. Given that it's rather vital to know its health at times, not being able to do so is silly.
• Guardians should report when attacked, just like they do when someone says or emotes in the room. Preferrably also say how much health they have left. Without that, keeping guardians alive could be extremely hard.
• Guardians should hear CT from the other planes, not just the current plane, in order to make coordination easier.
• Guardians should look as they move or track into a room, instead of requiring you to GUARD LOOK everywhere (which is a free action anyway).
• Guardians should be bulkier. It currently only takes about ten hits (or less) to kill them, which is very low given that they cost 200 power and the controller dies with them. I'm assuming they're already immune to critical hits, or they're even more fragile than I thought.
• Guardians should go to sleep if they're damaged and aren't controlled by someone. Currently, they don't heal themselves. Ever. Damage is permanent (or, at the very least, long-term. My guardian still has damage from the tests done over two hours ago, despite being dismissed).
• More abilities; currently, guardians can only web someone, shatter someones shield or shield himself, something available to everyone as enchantments. Given that I'm a non-com, I don't want to suggest powers here, although a power to heal health would likely help reduce down-time.
• A bigger suggestion would be to revamp how the controls work. Personally I'd prefer an aethership kind of interface; you start to control it, and you're transported to a separate room, get a prompt with the guardians health (and your own power) and you'd see says and emotes in the guardians room. You'd still use the GUARD commands to speak, emote and attack, and you'd be able to use all the normal commands as well (given that you'd be in a specific room controlling the guardian, you couldn't attack normally anyway) which would make it easier to use CT, coordination clans, etc. If the guardian dies, the room would implode aethership-style, and everything that drops from the corpse would fall out to the room it was killed.

Oh, and another suggestion: currently, the guardians last 100 IC days, i.e. a little over 4 RL days. This is a rather short period of time, to be frank; you'd have to create the guardian when the raid is happening to get some use of it, and as said before, since they don't regenerate health, its use is extremely limited. I see two solutions to this: Either A) reduce the duration significantly, but only have it reduce when the guardian is actually in active service (you could also slap a one-day instant decay on it to prevent the usual tactic of dismissing it right before the decay-ticks), or Give it some amount of power (perhaps 600) that is continually used as the guardian is active (i.e. not dismissed), and is also used for powers. Thus, a guardian that just walks around can stay alive for a very long time, but one that is active in combat will have a significantly shorter life-span. This also means the power of the user and the power of the guardian become separated.