Bold parts...
1. Where did it state he killed/revived 1000? He mostly likely killed about 50 or less and seriously injured about 100, which is still impressive, due to the fact Tsunade used her best healing tech. when his big attack hit saving if not all, majority of the population present there, as others were in safety (give her some credit too, you make it seem she did nothing as a Hokage

).
2. Tobi with one Sharingan and one Rinnegan in a short time was able to take Kabtuo's Edo's and make them his, while also putting tailed beast inside them and controlling them in full form, so...how was Nagato better at six paths VS Tobi?
3. Well, clearly he was no leader as Madara/Tobi started Akatsuki and were the owners/leaders of that organization, who got in touch with Yahiko and after his (Yahiko) death, used Nagato. When Edo Itachi/Nagato spoke remember Itachi said he knew more about Akatsuki than Nagato did? So, there is a difference between their ages, but yet Itachi (member of Akatsuki) knew more about the organization than this so called "leader" despite Nagato being around longer and an original member of Akatsuki.
4. Well as far as we know in the manga Tobi told Konan that he (Tobi) was the one who gave Nagato the Rinnegan. We can only
assume that seeing how Tobi im planted the Rinnegan in himself the same they
may have done with Nagato, so in other words Madara/Tobi gave Nagato this power of theirs. Kakashi and AO are best examples, despite their impressive usage of the Sharingan/Bakygan if they faced off VS top teirs (Uchiha: Itachi, Madara, Shisui, and I hate to say Sasuke...Bakyugan: Neji/Hinata's fathers, and possibly Neji) they would most likely get out shined with the eye, as they drain a lot more chakra than the actually users. Nagato in the other hand was a great for Rinnegan due to Uzumaki bloodline and had a lot of chakra, but he's no less like Kakashi/AO,
if indeed the Rinnegan belonged to Tobi/Madara it's clear they have the possibilities to do a lot more than that Nagato had, as far as tech wise we already saw Madara suck ninjutsu and bring down the meteor, we can only assume he can do the rest, we just haven't seen it and we've seen Nagato use it already a few times.
5. Well the same goes for Itachi despite his intellect lvl and his usage of Sharingan/MS/Genjutsu he has poor lack of chakra and stamina. Kishi over powers people, but also shows a weakness to them Nagato = cripple...Itachi = stamina/chakra. They both at the end have their respective dojutsu to cover up for it.
@OP Topic
As far as this battle goes, honestly Nagato would be lucky enough to even give Minato/Itachi a difficulty. I respect each of these char in the same way, but come on, your putting two Einsteins together, and people are actually thinking Nagato can win? Itachi at full with Minato at full would rape this.
If it was a one vs one against one another debatable (not getting involved in this), but two VS one? I'm sorry not just Nagato, Tobi/Madara/Hashirama would even lose this.
The battle can go like this, Minato with his speed can keep Nagato busy (assuming he isn't using 6th path), both (Itachi/Minato), can figure out strategy/weakness within secs. Itachi and Minato will figure Nagato out, max I'd give a min (on thinking of strategy/weakness that is)...TBH this battle can end before it even starts.