I launched there 2 weekends ago. I probably won't be back.
1- As you mentioned, the dock required me to climb down a piling to get in the boat and the back out on the way in.
2 - Getting out of the parking lot is nuts. You have to turn right on 61st street and that is hard enough because of the way the light is at 45. On a dreary overcast end of January day I waited nearly 4 minutes to get the opportunity to have a hole big enough to risk jumping out in to traffic to leave. Any hint of sun or warmth and finding an opportunity to get out of the parking lot will be impossible if they keep the lights timed as they are now.
3 - once you are on 61st and you want to head home toward Houston, you have to take a "scenic" route through neighborhoods and side streets to get going the right direction. Every turn out along 61st is a no uturn.
4 - even with signs posted to tell folks not to do it, people are already making the boat launch a fishing pier.
Nice try and great addition to galveston, but the traffic rules getting out of there will make it where I won't try it again.