I disagree with unionruler. Don't upgrade the hopes. At the very least they're the least important upgrades, and at the most, in my opinion, the ones you shouldn't, since playing them one turn earlier saves you much more often than 1 extra point of damage reduction in-game. Dragons are nice upgraded, but I think I'd go shards (2-3 more)=>electrocuters=>dragons (assuming 4 towers)=>optional (not recommended) hopes.