Against it.
It makes Tribalwars seem like other games which involve a lot of luck.
Some games have it so in attacks you can get in the report: "After a long tedious walk, your army decided to rest. While resting by a giant oak tree, the land around them opened and a leprechaun appeared! 'Oh jolly' the leader cried! The leprechaun sang them a famous Irish song and gave them 1000 extra loot."
I personally see bonus villages a bonus for new players. Randomly surprising them with an option to choose would either make the game easier, or terminate the whole competition of conquering a certain village which has specific bonuses.