I know your statement was aimed at another poster, but here you go:
Stats since 08-09 (Oshie's first year)
Player /age >> GP >> Goals >> assists >> Pims >> PPG
Mule/33 >> 292 >> 115 >> 107>> 205 >> .76
TJ Oshie/26 >> 292 >> 70 >> 125 >> 146 >> .66
Derek Roy/30 >> 319 >> 88 >> 158 >> 162 >> .77
Mule = $3.95, actual salary = 5 m, Team Cap % = 6.96
Oshie = $4.175, Actual 4 m, Team Cap % = 5.95
Roy = 4m, Actual 4m, Team Cap % = 6.22
I would take either Oshie or Roy's effort over Franzen's any day of the week.
Oshie is a good player, though, like Franzen, he suffers from spells of inconsistency. Roy does not fit with your comparison. You have left out the fact that he has been in inexorable decline for the past four seasons---to the point that exchanging him for Steve Ott was considered fair---and while he had excellent campaigns in 2008-2009 and 2009-2010, his past two seasons have assuredly left something to be desired. More, he is small and and average defensively.
Now I get that they all make less than 6mil which was one of your original requirements but here are just some names with 6m cap hits who I would take over Franzen:
(look at these names, why you picked 6 mil I am not sure)
Milan Lucic, Taylor Hall, Zetterberg, the Sedin twins, Patrick Sharp, Mike Richards, Toews, Kane, Tavares.
Then there are guys that depending on the day I may take over Mule:
J. Staal, Tyler Sequin, Zajac, St.Louis, Jeff Skinner.
Now can we stop saying that for the money there is no one as good as Mule, because even at a 4m cap hit he is not the discount people think.
I agree that comparing him with players at $6m cap hits doesn't make much sense, so there's no reason to discuss this.
But yes, he is a good value. A discount? Not really, but a good value nonetheless.
The fact he is actually paid 5m puts him in the company of a lot better players, with a lot more desire.
Actual salary isn't as important as cap hit. So there's that.