Thank you for the perspective, Performa01. To be clear, I certainly don't expect Siglent to grant every wish and implement every feature request; that would obviously be unreasonable.
More clarity would help to manage expectations -- e.g. your statement that four math channels just can't happen due to limited computational resources. I had suspected that, but had not yet seen a clear statement anywhere. More transparency regarding timelines would also be helpful in my opinion. I would strongly encourage Siglent to switch to a time-boxed development and release cycle for updates once an instrument is in "sustaining" mode: Set a release cadence upfront, say one feature release per year, then implement features incrementally until the drop-dead date for the test and release phase.
May I also say that the Siglent advocates here on the forum have set expectations pretty high. Siglent is touted as "the company which keeps developing their products and adding features throughout the product life cycle", and also as "the company which does not implement 'checkbox features' just to have them in the spec sheet, but does things properly". Seeing that the last major feature release for the SDS2000X+ happened two years ago, and apparently the next one will not happen soon, conflicts with those expectations. And seeing the very basic AWG in the same scope, and its lack of integration with the scope functionality, is not in line with the second claim.
I have nevertheless ordered the 2000X+, based on its current specs. It still seems to be the best match for my needs within the budget I have set for myself. But it was a painful decision due to some of the unexpected limitations, and I was hoping that the firmware update plans would make it a bit easier.
If you don't mind, I would like to throw in my 2c into discussion.
Statements on how Siglent keeps developing products are more than true. Track record speaks for them.
In my experience expectations by customers are almost always "too optimistic". From my own experience, with my own products. Nothing wrong with that, but customer expectations are not same as the promise by the manufacturer. Manufacturer might give their best to keep the platform live and vibrant or they can release it, fix glaring mistakes and forget about it. It is up to reader to do their homework which is which.
As to expectations, fact that Siglent is still keeping this scope in active development and keeps adding features long after release should not be confused with "Siglent promises to keep adding major features that will with time convert a 1000€ scope into same capability as 20000€ LeCroy".
Realistically, manufacturer will add features to keep scope competent contender in a marketplace where it belongs. They might add a bit more to keep it fresh and to keep certain strategic advantage. But mostly never it will grow so much to exit it's class and enter one above. For both strategic and technical reasons.
Unfortunately, I don't keep an archive of old datasheets and manuals so we can compare. Shame.
As for development and release schedules, that is also interesting and not so simple topic.
First, these touchscopes from Siglent are part of platform based on common code base.
While they don't share common FW in binary form, they share common framework.
Adding new features logically happens on platform level and then gets propagated to it's members, based on product placement, architecture and technical details.
There will be some implementation details specific to certain model. If that specific detail would require a separate, model specific, piece of code to accomplish something differently than the rest, than that is not optimal. In which case chance of that happening is not so high, unless it is something of vital importance. Sometimes, a feature is developed for higher models and propagated to all because it is nice to have and no problem to implement. Like mounting disk shares etc...
Development and release cycles are all impacted by this. This makes them highly nonlinear and interdependent.
In addition to that, modern practice to develop software on fixed released schedules without and regard to quality or completeness of code has shown catastrophic results for quality of code.
Just look at Rigol which released 4 different new scopes (4 products) based solely on management decision to stick to aggressive timetables. It's been half a year now... They basically released hardware-software prototypes, what Microsoft would call RC (release candidates). It is almost completely defined hardware and software developed to the point of software architecture largely defined and basic modules implemented in their first iteration.
This is what you get if you have to release software twice a year instead of when it's done..
Since Siglent is very mindful of their professional market (while Rigol seems to focus mostly on hobby market, strategically) they make sure their releases pass the litmus test before releasing. Of course nothing is completely perfect all the time, but they put in serious effort to do so. As opposed to blatant disregard to these principles like some other do.
I ask you to take Keysight and R&S as example an take a look how aggressive are they with releases and how often they do them.
And how many real features they added during lifecycle. Whatever they did add was to simply fix initial bad decision to artificially limit products in a first place. R&S added slightly better math on RTB2000 only after sever backlash by users that complained that 3000-4000 € scope had worse math than 500€ Chinese scopes. You still have to buy segmented memory and basic decodes for RTB2000 as a separate option.. Or Keysight with 1000X where they finally opened up DSOX1204 to have simply basic functions other much less expensive scope had for years. Basic measurement statistics was only added in september of 2021. and that was last release of FW for it. Since release there were only 4 FW updates (since October 2018).
None of the "big boys" will ever commit to any schedules or feature.
FW updates are in a way a strategic resource, nobody wants to open their cards..
I thing Siglent is actually doing a better job in this regard.