First, no build is good for all games. Second, you don't have any runes. Third, you've put mastery points to improve summoner spells that you don't even use. Fourth, you haven't explained why you like to build yi like this or written any tips on how to play and what to do. Even though i use a similar build i do NEVER put mastery points on more than 2 summoner spells since you can't have more than 2. AND why would someone want last whisper early game when no one have even begun stacking any armor. A very much better item would be tiamat which give splash damage and therefore making farming minions easier.
If you don't change this guide at all i will consider you a complet N00B