Yes, with the EU ruleset, the team with the disadvantage is encouraged to push. Why? Because otherwise they lose the game. The only motivation for a team to push with the US ruleset is because otherwise they will get completely bored out of their mind. When there is money involved, people are quite happy to sit there and be bored if it means they have an increased chance of walking away from the game with some cash in their pocket. This is why I'm a fan of the EU ruleset.
Excluding the scoreline, the advantages in TF2 are actually very small. You get a slight respawn advantage by having more capture points secured than your opponents, and a team with an uber advantage gets just several seconds of invulnerability. Even this advantage carries a risk, that if you do not accomplish anything with your uber push, the enemy team now has an uber advantage. Most of the time the uber advantage is partially negated by the 'defenders advantage' which includes height advantages and having a resupply near them.
The fact is, in a high stakes game, the advantage often isn't enough for the advantageous team to want to make a push with. So they will be content with staying put. TF2 having a clock is what promotes action during high stakes games and yes... the action comes from the team who NEED to make a play, which is the team who is losing.
This is the same in a number of sports. A team in football (soccer) will put more strikers on the field near the end of the game if they are losing. This means less defenders but it is a risk they need to take as they are the ones who need goals. Sure, the winning team might take off a striker and put on another defender because they are defending their advantage... their score advantage. This makes perfect sense and is just called being smart. If the defenders are too good at locking down, then sure, it might be boring to watch, but this is not always the case.
If you make it hard to teams to pull back points, it might encourage them to play smarter so that they don't get into a position where they are far behind and require drastic methods to get them back into the game.
So more onto the topic... if you want TF2 to be more entertaining / interesting, then you firstly need to play to a clock. Timers force teams to do something. Secondly, we need that round timer to actually come into play. Maybe change it so the round timer doesn't reset when a point is captured, but instead rewards half a point to the team with the most capture points after this timer expires. This should hopefully encourage more time based, ultimatums, whether that means a team might decide to just hold for 2 minutes or to make a push for the end of the round with nothing to lose. You will still get stalemates but they would be shorter and have more options for both teams. Don't know if that made perfect sense but rushing this :P