Where you see harm to TLJ, I see an enhancement.
Snoke was frequently quoting Palpatine’s style of speaking in the throne room. On the surface this appears to be an either not too subtle homage, or even what one considers lazy writing. At best, you might consider it a deliberate representation of the idea that cycles of villainous methods of manipulation repeat themselves.
And yet with the added context of TROS and its revelations about Snoke’s connection to Palpatine, this subtle detail from TLJ goes from being perceived as lazy writing to being a deliberate hint at a much more overt connection, one that became very obvious to me the moment palpatine’s return was confirmed, even if that wasn’t the author’s intent, it lines up very well. Snoke instead becomes yet another byproduct of Palpatine’s legacy, a front line soldier designed to pave the way for the Emperor’s return and trained to operate his agenda while Sheev himself readies the final Order. A tool to take over the Imperial Remnants from within while without putting Palpatine himself (whom is physcially unable to act directly) at signifigant risk. Snoke doesn’t have to be himself a “meat puppet” to accomplish this; the nature of his training can be left ambiguous and up to the viewer’s imagination (though canon has confirmed officially that he does have a mind of his own, if it’s any comfort to you).
This means Snoke dying in TLJ was the right choice, because he was always intended as a disposable ally to pave the way for something greater. The TLJ novel implies that he simply showed up one day and swept into the First Order and took them over, either through treachery or perhaps even by force. This makes a lot of sense when in the lore, Rae Sloane took over the Imperial Remnants and disappeared into the Unknown Regions on her own, disconnected from Palpatine’s intended agenda. Snoke then becomes the perfect means to take these assets back and steer the plan back on course. This makes Snoke a logical extention of how Palpatine used Dooku decades earlier, as a disopsable minion meant to pave the way for the real prize… a dark sided member of the preciously powerful Skywalker leniage. Palpatine uses a variation of his modus operandi because, of course he would. It worked near perfectly before during the Clone Wars, so why not try it again? Only this time keep completely out of sight until your power is absolutely secure. It makes perfectly logical sense when you take the ENTIRE saga into account (and not just JJ’s heavy bias towards the OT), and fits much better than the authors themselves may have intended because of this. Snoke leads the First Order, a front line attack force meant to weaken and destroy the Republic, effectively taking revenge on one Skywalker (Leia), while Palpatine targets and manipulates Ben from within to target the Jedi, getting his revenge on Luke. Snoke and Palpatine then share a psuedo Master/Apprentice relationship because of this, even though Snoke himself is not officially a Sith (something he shouldn’t be when he’s just an artifical being meant more as a tool to be used).
It is possible for TLJ and TROS to be internally consistent if you look beyond your own internal bias and see how others can interpret the material. It’s not even that hard of a thing to do. Just because it isn’t necessarily “deliberate” doesn’t mean a capable author can’t flesh out the lore this way in the future.
Sadly, we can only do so much with this cut without having new material to fill. A better explanation for Palpatine’s “son” within the film itself would be a great touch, but not one that I think we could do easily or tastefully, and ultimately a less important point than people might think.
I mostly agree with this interpretation of events, which binds TLJ & TRoS (from a plot/lore perspective at least), and I do want them to bind as neatly as possible. But as you note this interpretation doesn’t involve Snoke being directly controlled by Palpatine like a puppet. That’s my main issue with that line, that to the average layman viewer it could imply Palpatine was Snoke, or was directly controlling Snoke. It’s implicit in the line, though it could be interpreted in a number of ways, and as you say it was clarified that Snoke was his own person. But without that line there wouldn’t be a need for clarification. Saying “I made Snoke… the First Order was just the beginnig” gives us enough to connect everything without raising further questions, and as you say, leaves things ambiguous and up to the viewer’s imagination.
If a viewer is left assuming Palpatine and Snoke were the same or mostly the same character, then their view of TLJ is harmed, as to them ‘killing’ Snoke would mostly ammount to unplugging Palpatine from a host body.