The difference between LFR's and Swords is that LFR's are much more viable options to use in more scenario's. Swords are niche in areas they are useful, and only very few of them at that. They are very dangerous to use because enemies prioritize whoever is closest, and bosses love to spam stomp attacks. You will get flattened in seconds using a sword. Blocking isn't helpful because it consumes a lot of ammo, unless you're a Titan with Stronghold, but then you are giving up an exotic armor slot just to make blocking worth using. Even so, it takes too long to activate following a swing animation, forcing the player to stop their melee combo and wait to anticipate an attack. This leads to very low overall damage, even if the sword itself hits hard. There are only 5 good swords in the game, 3 of which are oriented towards PvP. The rest may as well not exist. Even of these 5, they don't hold up to the same levels as other power weapons: certainly not LFR's. The point I am getting at here isn't that the weapons themselves are bad, but that the environment of the game rarely allows them to shine. Swords could work if they weren't so dangerous to use. Scouts could work if there was more in the way of long-distance combat. It doesn't matter how many they add in these categories so long as the environment continues to play better to the strengths of others. Sidearms and Auto's actually do fit the combat ranges in game, but don't have enough throughput. There is also a distinct lack of useful exotics in both, especially sidearms which only have 1 exotic. Autos have more, but none of them are particularly useful except Suros, and that's more of a PvP gun.

Bungie doesn't hate autos and scouts. These weapons were the meta in Y1 of D2. Uriels and MIDA were extremely popular, and gamers were tired of getting teamshot by MIDA campers. In Y3 we will probably see a lot more sidearms and swords. Videos on youtube have already shown a preview of the exotic sword quest coming soon during Y2.

Oh yeah that one. Definitely tried pretty hard to forget it

Well that and Grog nozzle combo... Broke as fuk