It's not just full Biotic that makes a joke out of Reapers. Anti-armor in general plays a huge role in decimating Reaper forces. Looking at you Geth Hunters with Claymore Xs and Proxy-Mine debuff (another variant is one Geth Hunter equipped with Claymore Shredder/EB Mods, a Human AR Soldier with a Cerb Harrier/Mattock using EB and Piercing Mods, a QMI spec'd for Tac Scan, duration or damage Tactical Cloak and Arc Grenades and finally a Geth Engineer specced for turret buffing, Networked AI damage and AoE Shield Damage Overload). Good squad setups (assuming you have reliable friends) involve two Geth Hunters, and two Quarian Male Engineers/Infiltrators. GHs decimate armor and heavies, QMI/Es demolish Banshee Barriers and Maruader Shields. Tactical Scan on QMs enable Banshee two-shotting for Geth Hunters who debuffed with Proxy Mines and one-shotting Brutes. Sidenote: Proxy-Mines can also Tech Burst the electrical effect of Arc Grenades and detonate Incendiary-effect for Fire Explosions.
Preferred/Optimal Reaper Gold Maps:
Firebase Hydra - Brutes are bugged on certain spawns and the general floor layout of the map (their pathing gets them stuck behind boxes and crates most of the time), Ravagers may have a large open area to work with for sniping, but so do you and your team. Ravagers can be one or two shot by most anti-armor builds on Gold (only takes AR Soldier 15 rounds on a Cerb Harrier 1 to down a Ravager on Gold). Banshees can be EASILY kited on this map if necessary (in fact, you can outright ignore them and target the more dangerous enemies that spawn in larger numbers, like Marauders) and the spawns are all fairly open to any form of spammable attack(s). Objectives benefit from the large nature of the map, the only one of contention however is the Delivery Objective, as it can bug out and fall through the map at the extraction area if the carrier dies (so use those Ops Survival Packs if you are near death). Landing Pad is your typical hangout area for turtling up during this mission (basically, every non-objective wave you will be in this area). This gives you a huge vantage point to see the enemy positions from (they will all be spawning in visual range anyways) and the Banshees have to take two (sometimes three) breathers just to reach your position (they in turn, are dead in the water at this point thanks to Arc Grenades and anti-armor SRs/Shotguns). Grenades are your number one enemy here, but Cannibals shouldn't be getting past the large open area/pill box on the right due to weapons-fire from your team.
Firebase White - Yeah, yeah, we know how everyone hate FBWGG farming, but this map is seriously a nightmare for Reaper forces. Spawns are in open areas, Banshees can be easily bugged in the corner of the landing pad where troopers jump and spawn from (they warp to the top of the railing, and can't warp down; Benning/Glacier have similar bugs with the upper-story spawns that troopers jump from). Brutes 80% of the time are walking down narrow corridors/openings, making easy pickings for any anti-armor classes present. Jokingly easy FBWRG games work in reverse of FBWGG, you don't want Reapers spawning near the landing pads. You want to force all spawns to the lower levels by making sure all Landing Pad (and the mini-lab next to it) spawns are covered, thus creating what I call the "Reaper Turkey Shoot" as they proceed to funnel down the corridors and main path (Proxy-Mine/Tac Scan Ravagers and Banshees first, they are priority). Marauders and Cannibals are about the most dangerous element here, since Cannibals chuck grenades and Marauders in-turn, shoot the living **** out of you once you break cover. QM Engineers/Infiltrators are invaluable here for spawn-nuking with Arc Grenades and Proxy-Mine Combo Tech Burst/de-buff. Banshees can be controlled if the line/spawn integrity is maintained during the non-objective waves. Stay cool, don't panic, Banshees will break the line a good portion of the time. Just Tac Scan, Arc Grenade, Proxy-Mine debuff and lay into them. A GH with a good anti-armor setup can two-shot 'em easy with the above mentioned tactics.
Firebase Goddess - OH GODDESS NO! WHY?! Yes, it's true, this is actually a good Reaper map. "But Kyere! It's small and has too many narrow corridors, winding paths and a large open room in the center?! How do we defend that properly?" Congratulations, you just partially answered your own question, the Great Hall which annoys everyone to kingdom come on Wave 10 hack is actually the best part to mount a defense against Reaper forces. Turtle up near the far end of the Hall in front of the desk/table (Ravager shots can't pierce the statue for some reason, and it also allows a view of everything in the area) and get ready to tag 'em and bag 'em. Reapers are slow and lumbering by default, and the most dangerous one, i.e. Ravagers, can be one shot/one-clipped with most Infiltrator anti-armor builds (Tac Scan makes 'em even less dangerous). What about the vantage point that overlooks the Great Hall? Marauders and Ravagers tend to hang out there 90% of the time when given the opportunity. Arc Grenades and anti-armor/piercing mods equipped SRs/Cerberus Harriers on the Quarian Male Infitraltors/Engineers makes short work of them. Reapers (especially Burtes and Ravagers) get bottlenecked trying to enter the Great Hall's two main entrances (the left and right side from the position of the table in the far back). Objective Capping follows same rules as the above, a QMI (or any Infiltrator) with duration Cloak (though that's optional, I've done it without duration in my squad) caps objectives while the Team draws spawns. Wave 10 hack will be the most problematic, ASSUMING you don't just missile the damn spawns that creep around the corners. Seriously, missiles are your answer to Wave 10 hack zone, remember, you held your line for 9 waves. If they pour in during the Wave 10 hack, just kite, missile and kill. Ravagers take priority as usual, Marauders second and Banshees third (since these are missiled). Brutes tend to get stuck behind pathing Ravagers and Cannbals/Marauders. If you have delivery objectives, simply have one of the squad act as escort (as to avoid as much aggroing as possible since the Great Hall is where the spawns will be spawning at most of the time).
Thanks for taking the time to read this and hope you enjoy the event guys!