Line Orcs are great players in any Orc team and the myth you need all positionals are just not true.
You can build on a team using anything from 2-4 of any of the positionals and do just fine.
Sure... you don't want Block and +1MV on a lineman, you might as well buy a Blitzer. Linemen should simply be treated as expendable players and you will do just fine.
I think that you need at most 5-7 important positionals on any team and the rest should be low value expendable players. This give you more options to engage the opposing team without taking too much risk overall from a league perspective. It will also give you a much easier decision when time comes to renew your team from season to season. It will also give you some room for buying a rookie positional from time to time to train them up when you know that other positional players start becoming too expensive to keep around anymore.
The make up of teams in general also depends on how long your seasons are which often translate into how big in TV teams can grow. We tend to have relatively short seasons so TV don't really ever reach that high. This means that managing to keep your team well supplied with many skills on low TV players can get you pretty far. When top players rarely ever get more than four to five extra skills then keeping lineman's around that have a few skills can really give you a competitive team.
A team I have played in the past had (after some development)...
3 Black Orcs
Linemen: These should get some really basic skills such as Block, Wressle, DP, Dauntless (perhaps Guard on doubles, only as first skill is what I do) and you usually don't want more than two skills on them(or max 90.000 total value) and you cut them from your roster after each season if they are worth more than 90.000gp. Never keep them if they want to quit unless you have too much money. I usually ignore any stat increases on linemen, even Strength. Linemen are there to be used up not being an expensive player.
Blitzer: I would like to have one that is good at scoring so any double should be dodge and later catch if you manage a second double or MA, AG for stat increases. The others are just regular Blitzers with Guard, MB, Tackle. Any stat increase is worth it but I usually only like one stat increase on each Blitzer. I value skill more in general unless it is a late addition to their careers.
Thrower: One main thrower and an extra thrower if the main one gets injured. You simply want someone reliable to pick up the ball. I give the primary thrower Leader, Kick-Off return and then either Block or Accurate depending on the rest of my team. The replacement thrower should be similar but with no Leader skill, at least not until the primary dies or are not rehired after a season.
Black Orc: These are key players and I like skills such as Guard and Stand Firm on them... pretty much the only skills they need. But if they get a third skill that is Block followed with MB. But I'm happy with just the two first skills.
Troll: I usually treat Trolls as more or less expendable players and I don't want more than two maybe three skills on them. So, Guard and Stand Firm, the same as Black Orcs, are the skills I look for. You can't go wrong with Grab or Break Tackle either. You obviously want Block on doubles since it reduce the rate of "turn over" problems for Looner players.
Once you have your team really advanced you might need to replace linemen for rookie positionals such as Blitzer and Black Orcs... but that would be many seasons down the road. These Rookies only join the team to replace a star player that starts to get too expensive or fill the gap when one gets cut from injuries or simply die.
You want 3-4RR plus Leader. AG 3 and poor access to Block skill will see you fail quite often so you really need them. If you go Block heavy then you need one less RR.
And... remember... whenever your opponent's star players end up with their head in the mud... stomp them in the face and remove them from the game... the Orc way.