Doubtful really, Ba was expensive in January and not really a long term option. Not "super quality" if you will - not enough of an upgrade on Giroud. By that stage we would've been planning a summer spend on a striker.
A one year loan of Ba to plug a gap in the squad was a different and altogether more desirable option, but our real fuckup was not signing Higuaín.
Of course, it'd be nice to delude ourselves that had we sealed the deal on Higuaín in July, it wouldn't have affected the subsequent outlay on Özil, but I don't believe that for a second.
In short: there are a few ways to skin this cat, but whichever you choose it still ends up dead in a pool of blood.