Would be a shame to see its shield made into a personal shield due to the impact on its appearance (as well as making T2 arti even weaker than they are at the moment - i.e. countering a fatboy is one of the main uses of T2 arti and outside of that they're usually a really poor choice). While it's not functionality that tends to be used, it also nerfs the mobile factory aspect since units built by the fatboy are no longer able to be sheltered by the shield.
What about changes to make it a bit more of a generalist/all round unit? In terms of a few random ideas for buffing it slightly that wouldn't remove its iconic look (I'm not suggesting all of these at once but figured one or more of them might appeal):
- triple the anti-air and torpedo attacks on the fatboy (they'd still be very weak, but would have a slightly more noticeable impact against small attacks)
- Increase the shield health by 5k and decrease the main unit health by 5k coupled with a reduction in shield recharge time from 120s to 90s
- Make the fatboy able to build units while moving (I'm assuming this isn't feasible since I think it's been suggested a few times in the past and is related to the engine) to allow for a greater focus on the mobile factory part of it, or alternatively increasing the build power to be equivalent to 3 t3 factories instead of 2 t3 factories.
If UEF isn't considered to have sufficient options for assaulting an enemy base at the experimental stage of the game then another option is to buff percies very slightly.