No scouting is more randomness because you can't plan,
1. Its removing a element that some players paid for (VIP 3)
2. In general there is one thread per week or more that randomness is bad (AI, devour, gem drops, chests opening, etc)
3. Shenanigans WILL ensue, guilds logging defenses for others, plays changing teams mid day, etc. (getting around the "challenge")
4. The goal seems to be people are trying to get "harder matches"
In Guild Wars (and PvP) you should gain more points (and rewards) if you Invade with less troops. If your Invasion team is 3 Troops you would get a multiplier, if 2 troops it would be even higher still.
This adds to the risk and difficulty without removing elements of the game, rewards players that want a challenge BY CHOICE. It would only will effect those players that choose to try their luck with 2 troops.