TL;DR: Gallente should get a Light flamethrower, Caldari should get a Light missile launcher.

Intro:
I'm not sure if other people have noticed, but I really like what CCP has been doing with the feel of the Rifles and their "secondary" sisters. If you don't know what I mean, I'll break down how I view the rifles.

The Minmatar possess the Combat Rifle as the primary infantry assault weapon, yet there is also the "secondary" Mass Driver (which for all intents and purposes, I'm considering a rifle; also, a weapon that now has been shifted into the support/suppression role). In addition, the Mass Driver is an explosive rifle in contrast to projectile.

The Amarr possess the Scrambler Rifle as their primary infantry assault weapon, but they also have the Laser Rifle, which shares a similar role (although functionally different) to the Mass Driver, and thus acts a "secondary" rifle. Just like the Mass Driver, the LR contrasts its sibling by being a continuous laser rather than a scrambling laser.

I view this as a pattern amongst the races, and I'm hoping the Gallente and Caldari will receive their "secondary" rifles (I don't consider the Plasma Cannon the Gallente's; it's more in line with the Swarm Launcher as a Light AV, although it can be effective against infantry).

This being said, I'd like to bring to light my ideas for their secondary weapons.

Gallente - Plasma Ignitor / Plasmathrower
I know this has been brought up before, so I won't elaborate too much.

The weapon would be a flamethrower, but the plasma would be sticky and would continue to burn the enemy for a period of time after being exposed to the plasma. The period of burn after exposure would be some portion of how long the enemy remained in the AoE. So staying in the plasma for a second would result in little to no after-burn, but staying in the plasma for five seconds would result in direct damage from the plasma and also 1-2 seconds of residual burn damage.

Although I'm not necessarily in favor of this, having the burn damage be piercing and applied directly to the armor might be an interesting concept.

EDIT: I forgot to add this initially, but this weapon's max (hard-capped?) range would be about that of the AR's optimal range or somewhere between the CR and AR. The weapon would have a tighter spread (similar to the LR's stream) instead of having a wider spread and shorter range (like traditional flamethrowers).

Caldari - Accelerator Rifle / Missile Rifle
I've not heard as much hype about this one, but honestly this would be a weapon I'd be most excited to see.

Here is a video for reference of what I'm aiming at (note: It's the pink "handgun"; Bulldog Rocket Launching Rifle (RLR)).

Instead of being in handgun form, the weapon would be in the form a pseudo-rifle. The weapon would be automatic and have about 4-8 missiles per clip. The weapon would be a long range weapon, have a slower RoF, and have long reload time.

If you watched the entire video, you'll notice that the weapon performs well on stationary targets (it's EXTREMELY accurate), doing MASSIVE damage (generally one-shots or two-shots for heavy armor); however, with the least bit of movement, the rounds will miss and do an insignificant amount of splash damage in a small blast radius. Later in the video, the Magnaguard's Bulldog RLR is seen precisely hitting a small turret at longer-ish range, but enemies close by easily avoid the rifle. (I will also note that when using this weapon in SWB II, generally 1-2 shots at an enemy right next to the user will kill the user.)

I understand the SWARMs could be modified to do something similar, but I'd much rather have this as a separate weapon.

Conclusion:
I'd really like to see at least the Caldari Missile Rifle come to fruition, but I'd also like to hear what people have to say about the "secondary" rifle thing and/or present some additional ideas. I'll keep this updated as I get good feedback.