Chisora won't be fighting Joshua. He recently signed with Sauerland. They didn't just sign him up to feed him to Joshua. Matter of fact is Thompson could be a decent Joshua opponent at this stage. Joshua will send him into retirement just like he did to Kingpin.
He beat Helenius no matter what the scorecards say, he gave Vitali the toughest fight he had in years, tougher than Adamek, Solis, Arreola etc. He then went on a short winning streak beating gatekeeper Johnson and the then undefeated Scott. There was a period when he was seen as world class and a fringe contender. Chisora was clearly better than a domestic level fighter when fit and 2 of the local British fighters you mention that he faced, one was a former world champion and the other is the current heavyweight champion. Not bad for a guy who was never world class.
:deal chisora more than a journeyman a few years ago strong contender, now he seems slower with less energy hes just a gatekeeper.
I go with this pretty much. The two fights are totally different despite the parallels you make. The important differences are: Chisora's style ages very badly and also matches up terribly against AJ (power hitting - shot picker). Price was tactically and technically WAAY out of his depth against Thompson regardless of when in his (now hypothetical) career the fight takes place. Not so with AJ since Chissy is as crude as they come. AJ < 3 rds for sure.
Chisora is not nearly as wily as Thompson, Joshua not as chinny as Price, his style will work against him with AJ, AJ by KO3.
Thompson is now too old and slow to be competitive. Scott who beat him recently would be a better fight, if he had a better chin. I wouldn't mind seeing Joshua in with another quick and mobile heavyweight like Savon who ran circles around him in the Olympics. Maybe Cunningham would be a good fight to test his footwork.