The whole IFV concept is in question; the Israelis for example never adopted the idea of an IFV and the IFV concept was never really tested in a fair HIC.

A 25mm weapon (even if completely externally mounted and not costing a single dismount seat) should not be necessary on a Stryker. Stryker is meant to be an PC (and specialty vehicles), not IFV.
The infantry shall fight dismounted and receive direct fire support from dedicated MGS.
The problem is that the MGS is a big, not really agile but thin-walled target that hasn't enough ammunition* for its job.

the French have no really modern 105mm 6x6 AFV, bad luck.
A tracked vehicle like M8 AGS could have had better agility and slightly better protection at least. A real medium tank or medium-weight MBT of about 40 tons would have had all the desired capabilities except the unimportant C-130 airlift (which the Stryker AGS hasn't anyway).
Such a medium tank could have become the base for FCS and an alternative to M1A2 for heavy forces operations in difficult terrain.



*: The Russians used T-72 and T-80 in Chechnya and had to rotate their tanks because they ran through several times their on-board ammunitions stock during small battles like the fight for a village.