Great OP Terry!
The main issue is that most of the whingers have only watched the players concerned in highlights packages and a couple of games against us, and then feel knowledgeable about the player to spout their opinions. There are a couple of problems with this:
1) Unless the player is spectacular in the highlights packages, they are not noticed and the general opinions seems to be "he's rubbish, he never did anything". Indeed, apart from the fact that Rafa bought him, this seems to have been one of the sticks used to beat Lucas in the past; that he does not produce highlights, so pundits who only watched highlights of our games didn't notice him and then slated him. Indeed, Steve Claridge once slated Mascherano as not being worth £18m on Radio 5, before coming back on a couple of weeks later, admitting he was very wrong after watching him play a few times, and calling him a monster of a player.
2) For players watched in full matches against us before last season, Rafa used to set up the team to nullify the opposition's strengths, and as a result, we controlled games. When we won, it was always "the opposition did not play well". I don't remember many matches when Rafa was manager where opposition players stood out.
As a result of this, many ill-informed opinions are made based on players playing poorly against us, and a few highlight packages on MOTD.
Am I overwhelmed by the thought of signing Adam and Downing? Not really. But then I have not watched them for full matches week in and week out, so I am not really in a position to judge how they play, or more importantly, how Kenny wants them to fit into our team.. Is Downing worth £20m? Is Adam worth £8m? As individual players, I would say not. However, Downing provides width, some trickery and can cross well, all of which are things that we are sorely lacking, and Adam can produce the killer ball, so they may be worth the speculated amounts to the team. With our new owners, we are no longer wasting £35m to £40m per year on interest payments, so until we start any stadium work, that money can go into transfer fees/wages without the owners having to inject any more of their own funds.
We also have to remember that the rumours of Adam and Downing are just that. Rumours. As Kenny has said repeatedly, when there is something to know, they will tell us.