I've never found the off-site car-rental pick up place a hassle. I used it for the first time during my most recent trip to Vegas, and it was fine. It took me much longer to reach the one at DFW.
I guess the question is if you really need a car at all. If you're attending a meeting and don't plan on eating off-site or visiting lots of other places in Las Vegas, maybe it's better to do without. The hotel shuttles are cheap, and you could probably take 3 or 4 taxi trips for the price of a car rental.