I'm quite happy to admit I know nothing about players I've never heard of, nor seen.
Totally agree that it's almost impossible to know how a player will do in completely different circumstances, with completely different teammates, playing to a completely different system and objectives. I've been making the same point here for years.
I'd like to think I can look at a player and see what he can do where he is....but the whole reason big clubs let little clubs try to establish outside players at this level is so that they don't have to. It's almost impossible to tell how well a player will be able to do something that they haven't done yet. Only a rare genius like Peter Taylor could do that.
Given the lifestyle change, the football change, the physicality, and often the weather change, almost all players new to here take some time to settle and find the level. If they are going to at all. Generally at least a year. Of those that we are identifying as 'a success', how many have been fully up and running within a year?
Obviously if a player is miles above the level, they can look great even while adjusting and coming up to speed. Given the standard in the 'ship that doesn't happen often..... And it happens slower the fewer peer role models available to set the standards for the level.