If by dynamic you mean excitement and morale then that's patently not going to be true. I bet players like Foden, Jesus, De Bruyne, Aguero are even more excited about playing with Messi than we are watching him.
There is a risk in investing a lot of resources in one player but the only reason we can do this deal is because Messi wants to go. He's on strike. He tried to execute his release clause. The wages will be a drain but even when Messi is not playing he will still create huge revenue for the club. I am pretty sure that guys like Silverlake Investments probably knew about these plans and City will be set up to exploit that.
To be honest I do think City fans should acknowledge that at 33 he's not the player he was at 25 but it makes sense for City in a way that doesn't for Barcelona.
From a financial perspective, allocating/issuing equity to Messi as a payment is quite innovative (not entirely a new concept mind) in football.
for city, it would be like paying/issuing Messi with ‘x’ amount in equity which would be his investment in city (have a shareholding).
from a cash flow perspective, rather than have an outgoing in expenses (P&L), City use this as additional investment (carry it on the balance sheet) and generate further revenue (a given with the exposure messi provides).
higher revenue increases the value of the shares growing both messi’s investment and other shareholders.
trying to compare this as a transaction and it would be something like an acquisition by city of a revenue generating entity. Whereby city’s acquisition is more an investment in themselves to further enhance their revenue generation capacity.
In financial world, acquisition/merger of CYBG and Virgin money comes to mind in the last couple of years.
I think from a financial perspective, this is not going to cause any issues with ffp unless of course ffp is revised to address this (using cas verdict as an excuse to revise the rules).
Even then, It would be a case of Uefa cutting off the nose to spite the face by isolating city with Messi in their team and their commercial appeal at least on the short term.