The future will be us creating just a pure simulation and then after its done joining forces with Sports Interactive with their Football Manager series and using their database. The key will be if we take our time and perfect it we can provide gameplay to Football Manager and taking that game to another level along with our simulation having the realistic database.
I currently correct every (yes) players height/weight, correct foot too on PES 2016...
And for that, i use "sofifa", google research on differents website, and Football Manager.
And the winner about accuracy in general is... is Fifa by far.
I doubted about it, but no, they're really good at what they do, even if their rating system is arguable
For example too many player's who drops in every stats (even technical attributes, the stats are reduced globally not only physical) with the only reason they got transfered from a top championship to a smallest one, or getting olded.
FM have the largest database ever, but so many wrong height/weight strong foot according to many websites, youngsters especially. And very big differences.
I've noticed many players for well know league (PL, Liga etc.) height 190 cm in reality according to many website/images comparison, who's given 170 cm in FM.
The FM database is the biggest you can find anywhere, but full of mistake and randomly reproduced players, even with ressources they've got.
Before that experience, i thinked like you: "Football Manager have the most accurate datadase ever in terms of informations at least. Its a bible" but now that not what i think at all. Check yourselve if you have time to, you'll figure that i wasn't wrong at all.
The reality is that there isn't a single footie game with an accurate database, but it's not their fault: football is a sports with plenty of players all across the globe, too much to handle...
You can have a thousand of scouts, but if the clubs aren't cooperative with the community, it's useless
I know in the past a guy working as a "scouting reporter" for them, and for many players that's how they does stats for "not very well know players":
-They rate 3 or 4 stats, position, value market and current ability
-The rest of the attributes will be assigned a bit "randomly" with a program, as well as potential ability (even height/weight if the scouting report does not give informations about is shape)
-And then, you've got the player done.
So in brief, don't forget FM it's still a game and not a football bible, don't be a Mourinho. The best is to check on different websites and make you opinion.
But honestly, i was amazed at Fifa database accuracy, even if i reapeat, i don't like that much their rating system for logical reason i've explained above.