Yet Halo 3 sold more copies, has a larger player base at its inception and to date, than Halo 5 and CE. I was referring to the gameplay, not sales and playerbase.

Yet you praise Halo 5 and Halo CE? In which the magnum is the gun everyone uses? Everyone uses the magnum in CE and 5, but that doesn't mean that the other weapons are useless. The CE assault rifle can beat the magnum and the shotgun and sniper rifle outperform the magnum. The plasma rifle can stun enemies and the plasma pistol does more damage than the plasma rifle. The magnum is still the top of the food chain, but the other weapons still have use in the sandbox compared to their counterparts in 3. The Battle Rifle, DMR, and Sniper Rifle can outperform the magnum.

What do you think sprint, larger maps, and thrusters do? It doesn't increase lethality. It allows people who are losing engagements to disengage, which slows gameplay. You can also catch up with people who disengage by using the movement. For me, the gameplay felt no slower than previous games. The projectiles, hit detection, and BR make for a sluggish experience.

Halo 5 copied of all COD: Advanced Warfare's(which came out in 2014) EXO suit abilities. The movement may be similar, but Halo 5's movement is far more polished than AW's. A COD ripoff would be using loadouts and perks, which Halo 4 did. The arena-based gameplay in Halo 5 is closer to Halo CE and 2 as well as old-school shooters like DOOM and Quake.