Only because you didn't have the option to adjust it electronically.
Once you get used to it, it's one of those options that you don't want to live without.
I tested the ESA bike and although it worked very well if I were to buy another GS I would get one without ESA and fit my Wilburs.
The fact that BMW came up with a way to alter spring rate is very impressive as that is what is really needed more than anything when changing loads dramatically, and something Wilburs / Ohlins currently do not have.
Where the aftermarket gain massively is in component quality and fine adjustability.
All OEM stuff is always built to a price, I bet the factory gate cost of an Ohlins is at least four times what BMW pay for each unit (and possibly a factor of ten) They are also likely to be filled with low quality oil. The other issue is QC can be poor, often two bikes can feel very different, I know that the CSS have had R1's where the gas pressure in the shocks (on brand new bikes) can be 50% different and I suspect oil levels may not be accurately filled either - this is one reason why copying settings you see posted on sites and even in magazine articles is pointless.
As for adjustability I will move 1 click sometimes, and out of 20+ clicks on any adjuster that allows me to get it exactly how I like it, ESA must move the equivelent of 3-4 clicks at a time.
I can also choose to alter compression, rebound and pre-load independantly (and alter front and rear independantly) The OE unit gives 3 settings, none of which may be ideal for me and the button alters all parameters, for me I prefer a higher ride height for "sports" use, something ESA does not allow for as it only alters damping (OK selecting passenger will add pre-laod, but probably too much, also I only add pre-load to the rear to give a better steering response and I bet ESA would jack them both up when you select two-up - plus of course it also alters the spring rate so would make it oversprung)
If they bring out a version you can finely tune yourself (like the MTS) it would be very tempting to me, the other thing that is great with the MTS stuff is they have fitted high end Ohlins as well as provided the ability to alter the parameters to your own preference.
I think ESA is fantastic and a great improvement for anyone who would not have gone out and bought Ohlins / Wilburs (which I am guessing is well over 99% of owners)
I would not even go for Wilburs / Ohlins ESA as it still does not solve the lack of granularity I prefer, but again for 99% of owners this is another option to improve quality with the ESA benefits.