Truth be told, I find the question posted by the OP to be incredibly difficult to answer, especially since I have vivid memories of each players' memorable plays. I recall Mason in Dallas waving his only able arm towards Flacco after catching Anthony Henry with a double move and hauling in a TD in left corner of the end zone. I recall Boldin catching a TD in the opposite corner against Indianapolis with Darius Butler's arm under the ball. I recall Smith Sr. somehow staying on his feet on the 4th and 5 against Cincinnati after failed attempts by Dre Kirkpatrick and Emmanuel Lamur and getting loose for the long score. So I personally don't have a clear option as I can see there being a 1B, and even a 1C.
That being said, with regards to the points above, I don't think we can separate Boldin's playoff performance when we're weighing where he was when we needed him given that it was the stretch when we needed him the absolute most. It would be paradoxical with respect to the question itself. If every player on the roster had a stretch where they came in for three seasons and were largely responsible in one of them for SuperBowl run, they'd be viewed as a significant success and rightfully so. He disappeared in the stat sheet in a few regular season games, and he did have his fair share of drops, fair points. Arguably the worst was the aforementioned one against Pittsburgh, which was a potential-GW. It possibly his worst game with us, and it was an ugly receiving performance all around with both Mason and Boldin combining for 1 catch and -2 yards (To Mason's credit, he drew two penalties, though he did also had an OPI himself). That being said, Boldin's come through in the clutch before. One of the best examples would be the memorable GW 92-yard drive against Pittsburgh, when he had three different first downs, one on a 2nd and 10, one on a 4th and 1, and the last being on a 3rd and 8. I could be mistaken, but I believe that we only played Arizona once during his tenure, and in the game above, Boldin finished with 7 catches for 145 yards, 117 of them coming in the historic second half comeback, with 3 DPIs alone drawn in that half as well, so that one bodes entirely in his favor. The above mentioned drop label against Denver is dicey at best since he ran a slat and was forced to lean into the throw and attempt to grasp it with one hand, which he was almost successful at (
Link for reference), more of an overthrow than a clean drop. It happened at the beginning of the 4th quarter and he also followed it up with 3 catches for 47 yards, two being on a 3rd and 7 and a 3rd and 8, so it feels unfair to point out the single play and gloss over the remainder. He was rock solid for us through almost every playoff game, not just the 2012 run. He had that woeful and costly 1 catch, -2 yard performance against Pittsburgh, and it definitely shouldn't be discounted, especially because of the drop. The rest of it included 7 playoff games with 37 catches for 618 yards and 6 TDs, 10 for 174 and 1 TD from that coming in our 2 playoff games in 2011, so I disagree with the notion that he was as sporadic as they come. If we're willing to at least partly forgive Joe Flacco for his regular season inconsistencies due to his superior-by-comparison performances in the postseason, then we should do the same for Boldin. Personally, I'm with you in disagreeing with the any attempts to portray Boldin as a "golden god." He wasn't without his faults so that would be an exaggeration. I just wouldn't employ fighting fire with fire on the opposite side of the spectrum as it only fuels the other side. That's just my opinion.