It certainly does open things up to accusations of "retrofitting", so to speak. I think people who try to apply all.the.things to Jesus as far as the OT is concerned, are maybe trying a bit too hard, and I have to ask at that point "who are you trying to convince?". It takes nothing away from Christ to let Isaiah's prophecies apply to whomever, but also understand that the entire messianic foreshadowing was definitely a big OT thing to do, and so it's entirely reasonable to apply a dual interpretation to a certain extent without needing to do any sort of mental gymnastics to make it all fit. Christianity will still be okay if we allow Jews to have their own sacred texts and history without "hijacking" all of it. We also have the example of Ezekiel's prophecy (ch 28) against the prince of Tyre, that people have extrapolated to also have to do with satan, supposedly. When in plain text, the prophecy definitely applies to an actual human being who lived at that time (Ithobaal III), who was being called to task for being proud and sinful, and who was going to be judged. In fact, all of Ezekiel is plainly focused on Israel/Judah and the surrounding nations. However, somehow that got pulled out of its original context and applied elsewhere, and has now become accepted "tradition" and "truth" and "doctrine" ... even though it's admittedly a bit of a stretch ... especially since that prince/king of Tyre is plainly referred to as a man ... and you can see that it's a stretch when you pretend you know nothing about Ezekiel and just read everything at face value and put it in its actual historic context.