>1) Stability - it's light-weight aluminum, a joy to carry, but >the slightest breeze and I can see the vibration in my finder. >I have to be very aware of the wind when I'm doing landscapes. > I borrowed a unnamed movie tripod from a friend - built like >a tank - and immediately noticed the difference in stability. >Rock solid...but I wouldn't want to carry it all day.
All roads lead to CF
>2) Height - I have to raise the centre column by over 12 >inches to get a comfortable view height. This adds to the >stability problem.
That is why center columns get bad press. An too short unstable tripod is a bad combination when raising the center column to make up the diff.
>3) Head adjustments - I would like to be able to easily repeat >certain head positions and angles for still life shots, etc. >Presently I have to use an angle gauge and hand-held bubble >level to get everything lined up. My head also doesn't line up >perfectly when I flip it to portrait position. I have to use >the bubble level to check the 90 degree position.
That you may not find a solution for, especially with a ballhead, which moves freely in 3 axis. No matter what you do, you ultimately need to use a bubble or angle finder to make it repeatable. A pan/tilt head is probably easier, though, and why a lot of architecture shooters prefer that to a ball head.
>4) Quick release - my present tripod doesn't have a quick >release mechanism.
Like CF, this also leads one down the expense slope. Cheap QR's are expensive, they often suffer from plate twist, especially with heavy unbalanced nose-heavy lenses.
And that leads to L brackets and now you are paying more for a "simple camera plate" than you probably spent on your first tripod and head, and maybe what one plans to spend on an upgrade.
But all those "toys" have huge value. It's just a matter of deciding which problems you want or need to solve. The L bracket solves your problem of changing viewfinder height when changing camera orientation, plus it makes it easier to do precise framing with a ballhead. Ball heads do not like to be flopped over 90 degrees. They like to be reasonably level. The L keeps the head more or less level.