Yes.
You could have. Though, He didn't have the premierships, didn't play in the spine and wasn't in a glaring area of need for the club, so the comparison is ok at best.
Even still, the issue arose once he had arrived and we saw a pattern of poor output. It's at that point that his signing can be, correctly, judged harshly. Very few people were upset with Blair signing prior to him arriving. On paper, he was a fantastic addition. In fact, he was seen by many as the missing ingredient and one of the key reasons we were instilled as premiership favourites at the start of 2012.
If Luai was to sign (I personally don't think he will), and we see a similar poor output from him over the first part of his tenure here, then the fanbase will have every right to be upset with the lack of value for money.
But this is literally the case with every signing.