The powers that be here have told me not to expect speed increases, so that is not a reason!
I suspect it is really a “foundational’ matter, that it is MUCH easier to build upon CodeIgniter for both the EE programmers and for those who produce add-ons.
Of course, as some have joked…...with a basis behind it….future users of EE are likely to spend a LOT more money in total than before due to the numbers and prices of add-ons! If we get luckly, CI will allow for some open-source and free and low cost ones though!
So, does this document assume that they should upgrade, and then make the case? Or, does it question whether they should?
It’s amazing how much of the web runs on almost ancient code…..but if it was put together decently in the first place (and EE was), then it can work for a long time.
Personally, I will upgrade when I have some time to squash any bugs that will likely crop up (add-ons, extensions, custom stuff we did, etc.).....but my reasoning will simply be that EE has made the decision that this is the future path…
I get much more excited by new built-in features and benefits…than by foundational stuff!