Invades do nothing to make the game more enjoyable but can literally ruin the entire game for one team. It's not fun to play against, it's not fun to do, it's not fun...PERIOD. Make the game start sooner or don't let teams cross the center of the map until 1:30 and get rid of invading. This "strategy" isn't fun.
Let's say your jungle and your team decides not to come help you but their team five man invades your red. Then when they get caught they send one person to their red to stop you and hang out at your red to fuck you and since your red is top and their's bot they have a manning advantage. You now are fucked. You now get to be at a disadvantage for the rest of the game and if you're an early game champion that requires to get ahead of the enemy late game champion you just lost the game 45 seconds into it and there wasn't anything you could do to change that.
Get rid of it and let us actually play the fucking game.