Fender Stratocaster Thinline is a bad idea
This is the kind of guitar that says "just because you can doesn't mean you should."
Above is a Fender Eric Johnson Signature Stratocaster Thinline. For those not in the know, a guitar made by Fender or Squier with "Thinline" in the model name means it has semi-hollow body construction. I myself own a Squier Vintage Modified '72 Telecaster Thinline.
While the EJ Strat Thinline is a feat of engineering as it is (as far as I know) the first Stratocaster ever to be Thinline and keep all the traditional Stratocaster contour curves, I'm not all that impressed with it.
The really sad thing is that the EJ Strat Thinline is the first EJ model ever I consider a do-not-buy. Why sad? Because up to this point, buying an EJ Strat was pretty much guaranteed you were getting a great guitar. The EJ solid-body model in Lucerne Aqua Firemist, for example, is an amazing Strat guitar. Truly, it is. That's a guitar good enough to where I could say buy it without trying it first...
...but I can't say that about the EJ Strat Thinline, as I'm 100% certain that would lead straight to disappointment.
A quick history of why the semi-hollow exists
Some think the semi-hollow body electric guitar exists for the reason of weight reduction. While true a semi-hollow does weigh less than a solid-body, that's not the reason they were created.
The real reason behind the semi-hollow body was to combat feedback problems. When a traditional hollow body guitar is amplified, squealing/groaning noises, a.k.a. feedback, happens easily. When the feedback starts, the hollow body starts vibrating in the exact way you don't want to happen, and everything turns into a nasty sonic mess.
Semi-hollow construction greatly helped reduce feedback by introducing a solid center block of wood in the body. The top and bottom were still hollow, but with the middle block there, the guitar could be amplified without the worry of that nasty feedback. Most of the time, the center block is made from maple species wood.
Fender electrics and semi-hollow
The Fender Telecaster Thinline was introduced in 1968, but the famous one is the 1972 model year because that's the one that was released with the "Wide Range" humbucker pickups instead of the single-coil.
Stratocaster Thinline models are rare mainly because of the lack of wood in the design of the guitar. If you examine the Stratocaster and Telecaster side-by-side, the Strat has significantly less wood area on the bottom horn, a large front top cutaway, contour cut in the rear and another contour cut on top for the forearm area. A traditional Telecaster on the other hand is basically just a big plank with a generous upper top area and no contour cuts at all.
Those who have built Stratocaster Thinline guitars in the past purposely do not shape a forearm cut on top, and sometimes keep the edges more squared off to allow for more hollowing in the body.
The big deal with the EJ Strat above however is that it is, as said above, the first to keep all the contour cuts of the traditional Stratocaster shape and have semi-hollow construction at the same time...
...but was this a good idea to begin with?
In fact, no Stratocaster guitar should ever be constructed as semi-hollow because it just doesn't work.
The problems with semi-hollow Strat guitars
The main issue with a Strat semi-hollow is the voicing. Strats with the semi-hollow treatment, simply put, don't sound like proper Stratocaster guitars. What you get is a sound that's best described as "slightly off" when a trio of single-coil pickups are installed.
I own both a solid-body and a Thinline Telecaster. The Thinline has nowhere near the treble response that the solid-body does, but I knew that before purchasing it. What I got, and totally expected, was a pickup set with greater output and more midrange but less treble on top. And it works well for what it is.
It is true that Eric and Fender worked hard to voice the semi-hollow EJ Strat to sound good. Several prototype guitars were made with various degrees of wood cut out, and several pickup sets were made to get the guitar sounding right...
...for Eric's playing. That's the key thing to remember. Eric uses a lot of effects, which includes chorus, delay and of course fuzz for the lead tones.
When I watched video demos of the guitar not in Eric's hands however, that's when the the EJ semi-hollow showed its true colors. And it's just not a good Strat sound.
The deal with semi-hollow is that it's not supposed to be bright and spanky. This is why the '72 Telecaster with the humbuckers works so well and why it's so sought after. The particular combo of the semi-hollow with a pair of properly voiced dual coil pickups really works. But that's not what you get in the EJ semi-hollow. You get three "specially voiced" singles instead that sound like they're fighting against the instrument rather than working with it.
In the end, the EJ solid-body Strat is great, but the semi-hollow isn't, nor do I ever recommend even going near a semi-hollow Strat.
If you want semi-hollow, get one in Tele or ES-335 shape. Those are two that are readily available, affordable and have stood the test of time as semi-hollow electric guitars with a good, usable sound.
For the Strat, keep it as a solid-body. That's the body that makes a Strat sound best.