In my opinion, melee nerfs and guns buff is not a better choice.
I can understand developers want us to use more weapons. It's so upset to them if we only use few of those weapons. However, it's a game which means that each weapon can be calculated the upper limit(Damage, Crit, Status ...). As a result, the best choice is only few of them.
In the Warframe, we improve our weapons by setting formas to equip more MODs. Melee weapons have Stance MODs which means we can use few forma to have enough capacity and deal more damage. However, primary & pistol guns don't have this advantages.
In steel path, they may found that damage dealt by their warframes' ability/weapons is not enough. And our aim is to kill more enemies in a short time. As a result, the most easy way is to pull & control these enemies and use melee weapons to deal a kind of area of effect. However, most of guns can only shot them one by one. Kuva Nukor with a higher status chance & doesn't cause explosion repel Warframe will also be the best choice.
In some situations, we need to kill one Boss -- Eidolons-- Rubico, Vectis, Redeemer which have enough damage and best crit is better choices.
In conclusion, Game --> upper limit --> few weapons. New Players --> Stance MODs --> Melee weapons. Game Modes --> 1 Boss/ Enemies --> Rubico, Vectis, Redeemer/ Melee, Kuva Nukor. ===> Most of players use melee weapons, but use different pistol guns/ ability as aid.
So why not developed some new MODs as Stance MODs (for example multi-shot can auto trade to different enemies but not only one direction) and improve capacity?