I think a lot of the problems in cross code debates come from people either defending their code too much, or wanting the other code to be played like theirs too much.
The people who tend to either like both, or understand both properly such as Catalancs tend to make good, unbiased posts.
I take a lot of Dunbars points, only I feel the same way about League. I like the sport, Wigan are "my team" (I put the inverted commas because I follow them but I wouldn't say I support them). I went to Warrington away in the cup and it was a great game. Shocking defence as usual (my main gripe with modern League) but entertainment wise, I won't lie - not many Union games will top that and that's from a person who heavily sides with Union.
However I also watched the 2 Challenge Cup games at the weekend and really enjoyed them, both a complete contrast to that game. I saw people on the Warrington forum slagging the Wigan/Saints game off, but I loved the tension. Leeds and Castleford was even better. League is a great sport for me when the defence is tight. Keeps you on edge all the time. I actually enjoy seeing teams kick for goal as it makes sense in games like that. Again, that's my Union side coming out but despite Sale being rubbish and now and again choosing getting beat with spirit over winning ugly - I would choose a 3-0 win over loads of tries and getting beat any day of the week. It often winds me up watching a game of League between 2 big clubs, close game, scoreline is about 8 points in it, they get a penalty and go for a set of 6. I always think common sense would say take the 2, then the crowd boo which I never like.
I agree with the things you said about the scrummaging and line-outs. I don't think the line-out is a big problem really, but it can be time consuming. Scrummaging gets worse every year. I'd hate to see the embarrassing scrum that you get in League, but it gets reset too much. They should either have a time frame or a limit on how many restarts before you award a free kick or penalty. I realise this is often the outcome anyway, but sometimes they go on for about 4 or 5 minutes and it's boring. Yet at the same time, it's an integral part of the game. When you see a side like Leicester on a good day, they can drive a team 30 metres and that's how they win a lot of their games.
As somebody said - both games could take a lot off each other. People just generally make thick points though because they expect both to be the same when they're not. The gripes I have with League, I just accept. It's the way the game is played. People expect loads of tries and not much kicking. Speaking of which though - I do have to agree with red death though. I have a lot of League fans saying their kicking game has advanced over the years and is ahead of us. Yet whenever I watch it I rarely see it. Place kicking is fine and Sinfield is one of the best in either code. But a few 40/20's a season aside, I don't think the tactical kicking is very good. Though I'm not really sure what you can praise or judge it on too much anyway. You get to the 5th tackle and hoof it into the air, now and again resulting in an error from the opponent. I don't see how that's any different to "kick and clap" as the whole point is trying to gain territory or force an error. Only I suppose you HAVE to make the kick unless you're in for a try in League
