Fixing the specialist and class system
I've heard negative criticism regarding the implementation of specialists into battlefield. After talking extensively with the community on both Reddit, Facebook and Discord its not the specialists specifically which seem to be the issue, its a combination of factors. I'm also developer myself, so ill try and offer solutions which are some what realistic.
End of Game Voice lines
People don't like the end of game character lines and want to straight out remove them. I can understand that as they are tone deaf to the theme of the game, but removing that part of the end game script entirely could break other elements creating more headaches, so here's a better solution. Just disable the voices and voice animations, but leave everything else the same. I've seen this as a bug someone posted on youtube just after launch or maybe in the beta and its way more agreeable, and if anything a good way to show off skins.
Purpose in battlefield
Something that all battlefield players have always loved is feeling like a beneficial part something much bigger. Whether that healing team mates, repairing vehicles, providing ammo or spotting enemies and through doing this creates these battlefield moments that players bond over. They also want to feel individual when these moments occur, and hence their specialist should reflect that. Ill cover on how to fix these below.
The Class System
Players need to be part of a squad again to bring back that team play initiative that classic battlefield is famous for. The issue we have at the moment is no one tries to help one another outside of achieving unlocks because all specialist have access to all gadgets and grenades so the need to want to assist isn't there. Players don't feel fulfilled because their roles aren't defined or recognised. So to fix this all you would need to do is disable certain gadgets and grenades for certain classes, you could just 'grey them out' so to speak and change the UI more in depth later on if you wanted. Refer to Battlefield 3 or 4 for which gadgets and grenades should go to which classes. The Specialist are already in classes anyway, it just needs to be reflected. All weapons can still mix with any class.
Skins
On the battlefield all players want to stand out and appear different. So that if they appear end game they appear uniquely, seeing three specialists which look identical end game is a buzzkill and takes away the sense of achievement. To solve this you need to produce more headgear and body skins, helmets, balaclavas, a cloth over the mouth or face, maybe even different combat masks, gas masks etc. Be sensitive with the tone of the game too, nothing that people wouldn't see in some form of combat scenario now or in the future. You wouldn't see a guy in a santa suite or cowboy attire for example. For the sake of character building maybe specialist apparel like hats, bandages on arms, watches, glasses etc. These are basically mercenaries so they are military but individual at the same time.
Something to end on.
I haven't seen anyone complaining about the specialists unique gadgets directly, other than needing to be balanced. If people don't like gadgets you could always have a specialist gadget menu to assign to any specialist, but I understand that could be a lot of work.