It clearly is you as even as "the Generalists" and "The Jacks of all Trades" the individual units that MAKE UP the Space Marines army DO have specific weaknesses. Yes, a TACTICAL Marine is equally skilled in melee and ranged combat; however, SMs also have ranged specialists called Devastators that are better ranged combatants than Tacticals but have less melee capability. SMs also have melee specialists called Assault Marines that are better melee combatants than Tacticals but have less ranged capability, which is a weakness because even on the TT Pistols have lower firing rates and/or less range than the Tactical versions.

There should only be 4 Classes, not 5. Tactical, Assault, Devastator, Apothecary. Ground/Jump Assault should be within the same Assault Marine class, simply changing in function depending on what wargear you equip them with. If you remove the Jump Pack to have a Shield then obviously they are a "Ground" Assault Marine but more specifically they are still an Assault Marine.

CSM: Traitors, Raptors, Havoks, Sorcerers

Orks: Ork Boy(can spec for Shoota or Slugga), Storm Boy, Loota, Pain Boy

CSM is more a half-n-half between equipment and soldier upgrades, which is also how Orks should be, while Eldar are also more equipment-based like SM.