It is interesting that both Embiid and Jokic received All NBA votes at both forward and center. Jokic got more first team votes and more points overall, but both must have received more votes at C than F. Embiid had 414 points total, there is no breakdown of how many at F vs C. Tatum got 390 total points.
I am not sure how to fix this. Is it more fair for Embiid to get first team as a forward than for Tatum to get first team as a forward? Tatum also got guard votes but would have been second team as a guard (Booker and Doncic both had more total points as guards). The Tatum - Embiid thing is the only case where someone on a lower team had more total points than someone on a higher team. Should Tatum be able to make it as a guard?
Embiid is not a forward, neither is Jokic, yet many ballots gave them votes at forward. It is true that if there are two great point guards, they can both get in as guards.
This is complicated but here is my solution. Players can be placed in only one of the following 4 "positions", with a primary position and a secondary position. (Example, a player could be either primary SF, secondary PF (maybe applicable to Tatum) or could be primary PF, secondary SF (maybe applicable to Giannis). But those are the only two positions that a player could be selected for.
PG/SG
SG/SF
SF/PF
PF/C
Then the ballot has 5 positions (still 2 guards, 2 forwards, and 1 center):
PG
SG
SF
PF
C
For example, both Jokic and Embiid would be classified with the position C/PF (primary position being C). They could be awarded a first team slot in either position. Tatum would be a SF/PF or maybe a SF/SG. Brown would be a SG/SF. Doncic a PG/SG, and so on. But every player would have only one primary position and one secondary position.
Then, you take the top total points players. Last year, whoever between Jokic and Embiid got the most points at C, would be first team C. But if Embiid had more points, he could have gotten a PF slot with Giannis taking a SF spot.
Even my more complicated system is not perfect. You could still end up with say 3 true PGs with high points, but only room for 2 (one at PG, one at SG), but this is more fair to the centers by allowing them to be considered at PF also. You could end up with say:
Curry (pg)
Doncic (sg)
Booker (sf)
Giannis (pf)
Jokic (c)
Which is really 3 guards but more likely, you end up with something like this:
Doncic (pg)
Tatum (sg)
Giannis (sf)
Embiid (pf)
Jokic (c)
This assumes Giannis is given the position of PF/Wing and not PF/C and Tatum SF/SG, not SF/PF.
Complicated enough for you? In reality, Tatum is probably a SF/PF and Giannis a PF/SF so you still end up with 4 players (Giannis, Tatum, Embiid, and Jokic) competing for 3 slots (C, PF, SF) so not all of them can be first team in any case.