The defenders in CoX got basically the same ranged attacks as the blaster, but as a secondary instead of a primary set. This had several effects, for one thing the defender HAD to take the first ranged attack in the set on creation. In all cases the blast sets did less damage for the defender than they did for the blaster, but (at least in my memory) the secondary effects were more pronounced. The Electric Blast set was pretty bad compared to the other blaster primaries, but as a defender secondary, you could make a decent "sapper" build with it.

I personally would prefer that the Guardian ranged attacks not just be a nerfed version of the EXACT same ranger primaries, if that's possible.

Since guardians are, one assumes, going to be as concerned with buffing the team (self and allies) I would hope that whatever secondary effects their attacks get be geared toward damage mitigation in some way.

For example, here's a list of possible secondary effects that blast sets could have:

Residual Damage over Time
Knockback
Knockdown
Stun
Hold
Endo Damage
Endo drain (target loses, you gain)
Hit Point drain
Combined endo/hit point drain (target loses one, you gain the other)
Immobilize
Accuracy debuff
Damage debuff
Move speed debuff
Regen rate debuff
Recharge rate debuff
Endo Recovery rate debuff
Defense debuff
Damage resistance debuff
Mez Protection debuff
enemy perception debuff or ranged attack range debuff

If you look at this list, the more damage-oriented stuff ought to go to the blasters. Things like DoT, or vampiric effects the drain the target of endo (or do residual damage) and give you a slight heal (or endo boost) from it are definitely ranger material. Other stuff that might be desirable for the ranger, like Knockback or move speed debuff (to help keep approaching mobs out of melee range) might be less necessary or less desirable for the Guardian (I can heal myself, bring it chump!). The Guardian might rather prefer things that mitigate damage for him such that fewer heals are needed or things that complement the buff/debuff powers he has. For example, if I'm a Force Field Guardian, my powers give my allies and me +defense. Giving the badguys -acc might stack with that or it might be overkill, but giving them -regen or -damage would definitely help the fight in other ways.

So I think it would be cool if the attack sets are different for rangers than they are for Guardians, even of there's a lot of overlap in actual attack types and range/endo/damage stats, provided that the different secondary effects make sense for the class the attacks are intended for and there's some synergy with the other powers. That said, I expect there might be enough overlap in attack sets that you could end up making one or two ranger attack set into guardian attack sets, but I hope it's not the general rule that they're just going to make 5 attack sets and reuse those same ones for both classes. If this has to be the case to ship the game on time, ok, but I would prefer some variety.