So with the introduction of the campaigns I have started to adapt a new behavior, leaving games that have have virtually no chance of winning. Until i get my 10wins on all factions.

Why wouldn't I? There's no penalty and I generally finish my 10 wins on all factions on the last sat/sun so I don't have all the time in the world to sit 5-10min in a game I'm damn sure we will lose.
But it still feels wrong, if nothing else for the poor schmuck who joins in my stead.

What about you? Should anything be done?

I bail in a heartbeat. I'm a 100% solo player because I just don't have the time to join a guild This means that my campaign wins are tougher to come by, especially on LSM. If I'm on a map that breaks bad early I just roll out. Now if the change was 10 wins or 20 games played, I would stay.

Same as you 100% solo, usually i only play CSM, but got my 10 wins on the first day of the campaign, and knowing most new players would be playing LSM i decided to try to help them and get my 10 LSM wins, easier said than done.
Got up to 9 wins and i just can't bring myself to play anymore, endless games that are a loss before the timer has reached zero to start match, seeing grouped v LSM newbies, at the start i tried, i stuck with it, but after a few game i switched to bailing on an obvious losing game and tryed another, only to find the same thing.
Time to give up at 9 wins, not worth it.

i only start leaving if the cap bar is 95% full for enemy attack with more then 3+ mins left , too many team killers or alternatively its a fortress map as those are just too long and laggy for me other wise ive had matches who people have said it would be a loos and left only for more players to come in and clinch it (usually by working together)

I stick it out, can't improve if you don't face challenge.

The thing is you still get XP even if you leave during match
Of course during campaign victory is much more important but during regular pub this kinda cause big issues.

I keep playing even when it's obvious we're going to lose and play as though we can still win. It's a game, the main point is to play. When you run you change it from a probability that your team is going to lose to a near certainty.

if it's really bad, yeah I won't lie I'll bail out.

I'm talking like right off the bat the opposite side has triple capped and is running a 6-15 man guild vs pugs. just nope not wasting my time and getting frustrated.

Speaking from experience, games that put in leaver punishments create more problems than they solve. The person leaving has already given up, forcing them to stay will not make them try.

Sometimes when I get put into a game that's already going and the team is losing really badly I'll hop out and re-queue, otherwise I stay.