You made an interesting point. By creating injuries that last 18-24 months (assuming the program will induce that length - I don't know that it will) we can possibly create a work-around for injuries that in reality take 1.5 years to recover from, like the harsher shoulder or elbow injuries.
This would be good in that in
OOTP, when a player has recovered from an injury, he is 'good-to-go' and loaded to bear. Of course, this doesn't occur for those previously mentioned injuries IRL - it takes rehab assignments and so forth to get up to snuff (working the cliches here). So keeping a player 'OUT' for an extended period would smartly simulate that unavailability at the majors level.
Me likes that.
Now to see if it even works thusly. What I'm afraid of is that all I'll see are injuries in the 13-month max range.
But it is something to try.