This is what the current battle looks like. This is how 99 per cent of battles pan out - literally. I am not writing this because I'm a horde player, nor due to the fact, that the horde has lost Wintergrasp every 2½ hours during the past two weeks, but because when we - somehow - get enough population to win the battle, the Alliance suffers the same fate.
The issues lie with the battlegrounds not being populated enough. You can
not win Wintergrasp if you have 30 players participating on your side. It is still a marginal challenge, should you have a single, full raid of 40 players. Now, the Tenacity buff is supposed to compensate for the issue, but the values set per stack are not sufficient enough to straighten out the issue. Maybe it would have been, if the buff was applicable on vehicles as well, but it isn't. That could be a solution, however.
Alternatively, removing Tenacity and instead providing a reverse form of Tenacity for the team with the biggest quantity of players, that is also applicable on Wintergrasp walls and cannons, could be a solution. This would also reduce the damage of the RP-GGs (could also remove them altogether), which are harder to control when you're outnumbered. Ultimately, one could consider reducing the time and quantity of players needed to take control of a workshop for players with Tenacity.
These are just a few ideas. The thread is open for discussion.