Honestly I advise most people to avoid heavy weapons unless they are relevant for the situation/map. Heavy weapons are not an "all the time" kinda thing, they are great on fortress defense and hold the line defense. Yes even Shuriken Cannons are pretty good in those situations. Every now and then Reaper Launchers, Plasma Cannons, and similar type things are worth while on attacking. Most of the time though you need frontline troops, lots of them, and people bringing heavy bolters, shuriken cannons, tempest launchers, autocannons, etc to a camped door way like they are gonna breach the point with an m60 like Rambo are problems and its nothing unique to Eldar. Like if I had my dream every team would be like 70% DA's, 20% warlocks with enhance, and 10% fire dragons for vehicles who might swap out to other things as needed. Change those DA's for Reapers on camping defense situations. The same basic concept applies to other factions too imo. CSM is 100% MoN Traitors most with bolters a few with meltabombs/meltaguns if relevant Sorcs arn't worth it most of the time, melee isn't worth it, the weapons other than bolters arn't worth it, heavy weapons arn't needed, Raptors can't cap and don't contribute as much as a Bolter Traitor most of the time. Get an 80/20 Havoc/Sorc setup for defense situations otherwise just run them down with tanky bolter traitors. Orks are very similar to to Eldar, 70% Shootas with a mix of big shoota and regular shootas. 20% lootas with kannons or dakka deffguns based on the situation, and 10% painboys which can switch to other things situationally like shieldorks on offense. On defense congrats its 80-90% lootas and the rest as painboys. This is the only faction I'd even consider heavy weapons on both attack and defense just because of how strong the Kannon is, especially on attacking. For LSM this is where shit goes weird. You want tacticals with servo skulls and bolters, you want apoths with medicae grenades and bolters, maybe 1-2 shieldbros. The exact mixture of Tacs vs Apoths can vary greatly and isn't super relevant so long as you can get a tac to the cap consistently. Unlike every other faction though even on defense they need some Tacticals for servo skulls, so its probably like 70% heavy weapons, 20% apoth, 10% tac with servo skull. At the end of the day Reapers (and all heavy weapons classes) are not "main" classes they are limited utility classes that have niches to fill and they fill them well enough. That said they are the back bone of a camping defensive team and in that regard Reapers are "fine". I really REALLY wish people would use Reaper Launchers when they are relevant, though I think a large percentage of the player base doesn't even realize the secondary fire exists, how to use it, or that its a 1shot kill like the Kannon but with a smaller AoE that you can guide to the target. They can work fine even unbraced because its guided, just avoid the primary fire.