I think the real answer to this, for the system monkies amongst you all out there?

Can you prove that the other non-only-Force Sorts can be just as effective in their niches? Like someone who focuses on Lightsaber combat, at equivalent XP, and likely upping their relevant Trait in the Talent trees, beeing just as scary as said Force Using Specialist.

Because if so, then there really isn't an argument here. If not? Well, then there might be a good one as the OP claims.

Personally, I'd wager that someone focusing on Trait boosts will be at least as overpowered, if not more due to the far more general way that maxed out trait can be applied to other things.

Brawl Based Lightsaber Duelist anyone?

Or heck, any of the traits. Since they're all covered by one style. Can we take a Lightsaber style + one other spec and be just as broken by One Trick Ponying?

I've played and run games with a mix of "Lightsaber Specialists" and "Force Wizards," with the later concentrating on powers like Move and Bind (the latter of which gets nasty if the PC doesn't mind or care about generating Conflict to use those Dark Side pips for some easy damage) created at Knight Level.

The Lightsaber Specialists probably were more devastating in combat, since at 3 proficiency dice they tended to plow through anything that wasn't at least Adversary 2, which only slowed them down a little thanks to Breach 1 allowing their damage to blow through the target's Soak Value. An Ataru Striker with Hawk Bat Swoop and Saber Swarm can be absolutely brutal even with just Force Rating 1, while a Soresu Defender can pretty much negate most of what you're sending against them in terms of attacks and even make you pay for it with Improved Parry and Improved Reflect ( especially if they have Defensive Circle). A Shii-Cho Knight can be a machine against minions or even if just engaged with multiple opponents thanks to the Multiple Opponents and Sarlacc Sweep talents. Makashi Duelist with the Flourish and Finish talents are a nightmare for rivals and nemeses, and if they happen to miss, then it just got harder for the bad guy to hit them. Niman Disciple doesn't really stand out that much as a lightsaber combatant in contrast to the other five, but it makes up for that for having a bit of Force Wizard to it.

The Force Wizard that concentrated on Move could deal out a lot of damage... provided they had big enough objects to throw and could generate the necessary Force Points; tall order if Force Rating 1, but even then not a certainty with Force Rating 2, as the PC could always roll dark side on both Force dice. If they went for the Dark Side option on Morality, they had better odds of triggering the power.... but were generally limited to the base power and one upgrade. So high damage potential, but not exactly reliable unless you're within short range of both target and the thing you want to hurl.

For Bind, this was less about damage (although going with Dark Side for the Morality option does include a slight bit of damage without having to suffer strain/conflict in turn) and more about action denial and penalties via the Strength Upgrades and strain damage if the target acts while under the power's effects. But you also need to have Force Rating 2 in order to take this power in the first place, so for a Knight Level character that kinda cuts into your available XP.