well don't know whether this pally is your main char. If it is the case we are talking about completely different gearlvl. In our raid the warrior usually are between 1-5 in dmg with an enh-sham and a rogue in between and just in few fights one or two warlocks and/or mages on top. So the warrior is a reasonable DD in endgame, especially compared to ranged DDs, because we're not depending on mana and just need a heal once in a while...

How many physical damage DPS classes would you need to have one rogue going Hemo viable for the raid?

I hadn't heard of any DPS warrior in a good guild saying he can beat the good rogues. And to be honest, if a DPS warrior could beat rogues, it would've required immidiate patching from blizzard. You bring the first warrior for battleshout and then give him rogues to benefit from it as they do more DPS. More DPS warriors don't bring more battleshouts unless you run a 2nd full melee group, which will have other major disadvantages. If it's not a full melee group then you're again missing out on group synergy. That's why it's generally sub-optimal to bring more than 1 DPS warrior to your raid if you don't have attendance/skill/gear issues dictating otherwise.

Its not a matter of how many physical dps'ers, 2-3 will eat up all the charges just fine. It is the matter of Hemo charges not scaling nearly as well with gear as the Combat spec. As a general guide, if you are in a T4 instance, a single Tri-Spec Hemo (11/2x/2x) rogue is worthwhile. If you are in a T5 instance, its a wash. If you are in a T6+ instance, all your rogues should just be combat to maximize raid dps.

This issue was discussed at length in several rogue threads, most notably in the now locked Combat vs Hemo point of inflection thread (naming might be slightly different, but close).