Typical roller coaster I've experienced with hundreds of clients is...

layout: small
excavation: pretty big!
shotcrete-finish: what we expected.

Hopefully you had a scaled design and not just a rendering.

YES, definitely.
Felt the same way building a house. Looked at the stakes for the garage thinking, "there's no way two cars can fit in here" but after it was built, there was room for a third car!

My pool definitely looked the biggest when it was filling with water and we were standing in the middle of it. (see blog link)

The one thing that surprised me after filling was how deep the middle of the pool was. I guess I was used to pools where it was shallow/middling and then a sudden, steeper drop-off to the deepest part. If you've looked at my blog, I expected this spot to be around the bend to the right, east of the spa spillover.
Instead, I can't stand with my head above the water past the long bench on the east side (even with the corner of my lanai). I have to swim to reach the bench on the left side of the spa instead of walking up to it.

Definitely be around for the shotcrete if possible. If you've read my blog, I wrote about having the guys adjust the width of the steps after seeing that they were narrow and steep. I would have done more except the pool light was right up to the new extension that I had them shoot.

If something doesn't look right, SAY SOMETHING RIGHT AWAY, so that they can fix it or at least reassure you that it is fine. My PB didn't like the way the short diagonal wall looked along my lap lane and had them scrape off some - it would've stuck out just a bit (not that I can swim that straight anyway). It just looks weird because the lap lane is not parallel to that diagonal wall and your mind wants it to be. The geometry won't let it.

Also we refused to accept the electrician's solution because frankly, he was lazy. He ran the electrical up through the attic and dropped down to switches in the lanai. But, he was going to drop the cable along the outside of the wall and have a big switch box sticking out. Looked crappy. So we ran the conduit from the attic down the inside of the block wall and out a hole, so now the switch is recessed just like any wall switch you have in your house. He wasn't happy, but too bad, we're the ones who have to live with it and we weren't going to have to fix it later after paying him to do it right.

Here is a link that might be useful: Pool filling up from my blog