ePortfolio, Student information system, Repositories, ... are separate systems. We should integrate with them well, but we cannot build best-of-breed versions of these within Moodle,
comprising the Linux kernel, and numerous applications created by other projects.
Is that not what I mentioned above? Why waste time on developing a wiki when mediawiki is available? How about tools like WordPress as opposed to the blogging mod? Would integrating such tools not be a better option? Re-inventing the wheel is not always a good option.
Building something that integrates into a single interface is a better option, as you have already pointed out, twice... then why does Moodle not do that? You obviously support that model, otherwise you would not have mentioned it. Perhaps we are not that far apart at all.. I am sure there are any number of smallish tools that perform a single function or do a number of important functions but are underperformers in their own right. Could they benefit from inclusion into Moodle? Could Moodle use them to expand its capabilities?
I know it is certainly not a straight forward job, and may not be possible in every case, or develop a new tool without major rewrites, and in some cases it might be better writing a whole new module. I know I seem to be making simplistic statements and asking simplistic questions, but I do know a little about coding for a large, well established, products. I also understand that shortcuts do not always lead to improvements, nor to a stable product, ask Blackboard about that. But that is one way how Moodle could stay in the game and not get left behind.