i like Lydiate, but my problem is he is too 1 dimensional, he doesn't offer anything in attack. Thats why i think overall Croft will be the better choice against the pacy aussies -not to mention his much better lineout ability.
Either way if lydiate is thr number 6 and tipuric at 7, i be confident we can win BUT if we are chasing a game and need to score i would probably prefer a more attacking threat 6.
Not sure how many times I've said this, but rugby is not just a bunch of individuals, it's about the team as a whole and the balance of that team. Lydiate and Croft are very different players. Lydiate offers the grunt work, not just in defence, but in attack as well. He'll be there to carry the ball around the fringes, clear out a ruck, protect the ball, or even force a turnover (2012 v France for example). Players like him are required.
On the flip side, Croft offers his own attributes. He's less likely to be involved in as many rucks, instead lurking further out in the backline ready to take advantage of any opportunities. This brings its own advantages and disadvantages. He also offers a big lineout presence at the tail, something the Lions may need against the Aussies.
Ultimately it's all about getting the balance correct. If there are enough other players to take up the grunt work (O'Connell, AWJ, Warburton for example) then Gats may deem that Lydiate isn't required, and he can take advantage of the extra attacking and lineout prowess Croft offers. If on the other hand Gatland believes he has enough open field runners, and would prefer to really take it to Aus up front in the tight, then that's were Lydiate comes into his own. Regardless of how exceptional some of the try's Croft has scored have been, the one for Leicester not too long ago for example, there are other players capable of doing the same, namely North, Cuthbert, Halfpenny and the rest of the backline. Those backline players can't offer what Lydiate does in the tight.
So discounting Lydiate because he's not as flashy doesn't hold any merit in my eyes, neither does discounting Croft because he's not as good in the tight. It's all about the balance of the side as a whole, and what the Lions need most from their blindside.
There's always a more in between option of playing SOB, or even moving Warburton to the blindside, so don't discount them either.