The downside as a goalkeeper and killing people near the goal is they spawn right back behind you =(
Well I personally think it's an unfair advantage. As a high str goalkeeper I only had to stay near the goal, with an overhead attack ready and it was a guaranteed kill. However, the spawn mechanics are being changed to avoid spawnkilling so this shouldn't be a problem in the future.
The best tactic to score when the goal is protected is just like in handball, spread out around it and make quick passes. Additionnaly, in this game you can neutralise the goalkeepers for a short amount of time, or at least force them into fighting you. That leaves the goal quite easily opened. But of course, scoring isn't a matter of one diva running towards it alone or doing a lucky long shot. Scoring requires a team effort and that's nice.
Maybe if the goal is too easily protected, we should modify the maps to make the gamemode more alike to handball. In handball, defenders and attackers alike aren't allowed into a specific zone near the goal, which leaves it harder to defend. I think it's possible to do this using invisible walls.