...the client was just as riddled with bugs as it is now, but you had not invested any time/money in the game yet?
If new player retention is something that Riot is truly concerned about, I would expect a stronger sense of urgency regarding getting this client ironed out. The client is the first thing a new player interacts with, and let me tell you, based on my experience with new accounts, it is NOT a good look.
If first impressions are the most important, the League Client as a human being would give about the same impression as a couch-surfing leper who hasn't bathed in a few months, but sprayed themselves with enough cologne and kept their clothes in good enough condition to appear at first glance perfectly healthy and normal: everything seems perfectly fine until you get close, and you spot the sores, and smell the weird mix of Axe and piss.
Sure, I'm not going anywhere, but that's because I have thousands of hours and hundreds of dollars sunk into this game.
If I just started today I would look at this client like it was some kind of shady cash grab not worth looking at twice immediately after it asks me to choose my first champion, but all the choices are invisible.
Maybe, though, I would get past that because I enjoyed the tutorial game enough, and would play up until my first match against real players.
**"Boy I sure took a beating,** hypothetical me would think, **"oh hey look at this, I can download and watch the replay! That should help me figure out where I went wrong!**
*A CRITICAL ERROR HAS OCCURRED!* **Computer is soft-locked and needs to be restarted.**
**"Hmm."** I would think, **"This reminds me of some cheap knockoff game from China, the main purpose of which is typically to collect personal information for sale to advertisers, and is of low quality because the primary purpose of the software is not entertainment and the developer wanted to keep costs down by hiring amateur programmers. I had better uninstall this possibly malicious program before it causes some kind of damage to my computer. I already had to deal with a softlock, who knows, maybe it will brick my machine next! I sure can't afford to replace my computer right now."**
I know, seems extreme, but a lot of people have grown, are growing, and will grow up with technology, with cheap apps that don't deliver what they promise, and will notice that they come with bugs and annoyances, and will associate those bugs and annoyances with a lack of quality, and anti-consumer practices, whether consciously or unconsciously doesn't matter because after the first impression is made they will not come back.