Inspired by the post in the Role Master section... I'm speaking here of SM2 since I don't know how it works in Privateers. To quickly recap the salient points from SM2 then:
The combat round is not quite the same as RM. It is essentially Orientation / Psion Phase / Fire Phase A / Movement & Maneuver / Fire Phase B / Melee Phase. Most hand weapons are capable of firing twice per round (i.e. once in each fire phase). This means that the Teep is even more disadvantaged at low levels than the pure spell users in RM, because he has to sit through twice as much action before he gets a turn. This is accentuated by use of preparation rounds...
Since Teeps and Semis are not that attractive to most of the players I game with (the attraction of space ships with BFO guns seems to be the thing, and TIERing weapons, while cool, just take way too much development for a teep who is already spending large chunks of DP on psion lists).
However, it is an issue, and even at 5th level PC Armsmen are becoming too powerful, too fast. Having played a teep myself to a decent level (high teens) I can vouch that telepaths are even more powerful than the RM pures, simply because they are the only 'caster' in Space master. And as a result their lists cover the better aspects of many of the spells users in RM. All this leads to an even greater imbalance of arms users powerful at low levels and teeps powerful at high.
I have been toying with an idea to combine the SM rank system with the improvement system of RuneQuest - where the skill user gets a chance to improve his skill if he first uses a skill successfully, and then makes an increasingly difficult advancement check - in RQ that is represented by rolling your skill, so the closer that gets to 100, the less chance you have of getting a skill up. In this (proposed) amalgamation, I would transfer psion lists to become skills (so you'd have essentially a skill of Thought Into Pain or Control, or whatever, which would then create a level playing field for improvement, eventually requiring the PCs to find people skilful enough to train them (i.e. adventure hooks!) but still doesn't help the "combat monkey owning all" thing. The skill ups in weapons would logically translate to OB, while in psion lists they could translate to the maximum level the telepath can access on that list.
My next set of thinkings is again RQ-inspired, using a nice set of skills from RQ3 in the Sorcery section. These skills allowed you to manipulate the effects of your spells, make them more powerful, and so on. While the actual skills themselves wouldn't work, the concept does. So for example, I might have an "Attack Twice" skill (no stat, like Ambush) which you can develop, but in order to avoid jamming your finger in the trigger when you try and shoot in Fire Phase B, you need to break 100 on that skill first. This could be followed up with other skills such as "Machine-gun trigger" which allows you (having succeeded your "Attack Twice" check, have a chance of being able to squeeze off a third attack at reduced OB and increased fumble range in the Maneuver phase... and so on. Some skills may require specially-modified equipment.
In a similar vein, have skills for the telepath like being able to develop the "Two Track Mind" background option through a skill, or be able to squeeze out a second psion later in the round.
I get the feeling that this idea is half-formed, and has some holes (e.g. if you use this advancement for weapons, does the armsman lose his principal benefit of having lower combat skill costs?)... So any suggestions on how to level the field with pure arms users who can already attack twice per round with some frighteningly powerful weapons... would be welcome