Johnson may have come into criticism for not being up to par at times for England or Liverpool in recent years, but there's a huge difference between performing for those sides who both have fans with massive expectations (e.g. winning the Premier League, or a World Cup), and performing for Norwich who ultimately would be content with 17th next season (although hopeful of much better). I think if we signed him he'd soon look like a big fish in a small pond and he'd stand out as one of our better players.
He has perceived defensive weaknesses, but esteemed for his ability going forward. That's the exact same criticism that gets leveled at Olsson, and he wouldn't be considered good enough for Liverpool and England either, if Johnson was as good at defending as he is going forward then we wouldn't have the luxury of debating him as a potential target, because Liverpool would have extended his contract.
We'd have to be wary of him not being bothered and just wanting one final payday like Shaun Wright-Phillips though, who was also once a top 4 player and regular England international but showed little evidence of it at QPR, so no 4 year deals or anything silly like that!
Comparing him with Whittaker is just silly though. If Whittaker had signed for Liverpool he'd of managed far fewer appearances than Paul Konchesky managed, with the rate at which Liverpool discard their flops (several each summer) Johnson must be a good player just to have managed 200+ games. Whittaker has looked decent in a far weaker league, whilst playing with one of the leagues strongest sides, but is just not up to scratch for the Premier League and needs replacing. In my opinion.
Drogba in his younger days was a bit more than just an aerial threat as well. He had the strength and composure with the ball at his feet and the pace that Embolo shows.
