That goes against Riot's paradigm for Assassins of "Feast or Famine is bad, mmkay?". There has to be a good balance of Bases and Ratios. If they're all Bases, they get built Tank and still kill people. If they're all Ratios they struggle very hard in lane, probably more so than they should, and are useless if put behind. That's not the bad part of all Ratios, the bad part is if they get ahead as little as one or two kills they become absolutely unstoppable, even if they didn't outplay through opponent and just got a gank for them or cleaned up an early skirmish.
When there's a good balance of bases and ratios, the Assassins can do things in lane within reason, and potentially kill their lane with good play allowing them to be reasonably stronger.