The RVN-4X has been the hardest mech to play for me so far.
Its role in my eyes is harassing heavy and Assault in terrain where easy escape is possible with jump jets.
TL;DR Summary:
RVN-4X-LPL/TAG(Enemy reinforcement disruptor)
Target priority: Anything with it's back towards you, fire again if reasonably certain to get in a hit and be able to escape before he starts firing at you.
Jump jets for extra hit & run capability.
Harass Heavies and Assaults, break ecm cover with ecm to find softspots on targets any tag bonus rewards are secondary. Machine guns... why? I like mg!
Swap to SRM2 if you prefer that.
RVN-4X-ERLL(Harass Sniper/Brawler support)
Target priority: Anything you are able hit the same armor piece of. In my case: a darting lights=no, a stalker busy unleashing lrm rain=yes
Jump jets for extra hit & run capability.
Main role: Support the brawlers of your team, Long range First hitter.
Secondary role: Destroy stalker/catapult arms from a distance(Component destruction in general), Behind enemy lines guerilla "sniper"
TL;DR End.
Detailed breakdown of builds and thoughts regarding Raven-4X
RVN-4X-LPL/TAG(Enemy reinforcement disruptor)
This build was the one that I found most enjoyable(not the highest scoring, but the build that didn't bore me after two rounds)
LPL/tag combo?
Yes, It makes up for the poor speed of the RVN-4X to have that extra range and most of all, Pulse Lasers are harder to track for enemies, you don't reveal your position so easily(that's the feeling I got from using it).
The tag is there to
break ecm cover for your target so you can go after their most damaged parts, secondary use is as ecm breaker for team.
The machine guns are actually a waste of space really and optional, srm's might be preferable I like the mg's though. Their role in this build?
Primary: Make enemy mech's damage display flash, unnerving them.
Secondary: Backup weapons if your other arm get's blown off.
The most important thing I keep forgetting(at my skill level) in this mech is: Do not attack mediums or lights head on, use jump jets and harass your enemies.
The most important and sadly limited role that the RVN-4X can excel at imo is backstabbing enemy reinforcements just as they try to join a fight.
The point of it seems to be to tap incoming enemies and make them try to focus you for a few seconds while you fly away with your jump jets. That's a few seconds of enemy dps denied to the enemies side in that fight.
It is an ungrateful task however, you don't get rewarded or acknowledged for it, but if you are like me, feeling that a 75k cbill win with awesome tactical game play is more fun than a 150k cbill mass slaughter, armor tanking win/loss.
When I want to grind cbills and play RVN-4X I use dual ERLL build.
RVN-4X-ERLL(Harass Sniper/Brawler support)
Acting as sniper/close support with the speed to relocate quickly, even circle around behind enemy lines and cause chaos among enemies(very dangerous! shoot once and relocate or you will be hunted down by lights/fast mediums)