Ok, thats your opinion guys... but I think you really just follow what everybody says, your not doing numbers and also are not taking a look at the benefits when you are building items.

How can you say Muramana is good on syndra?? because just her ultimate?? and then you build Warmog's Armor???? did u realize that you need in total 2100 + 2650 = 4750k to build 2 items, that requires 2 slots in your inventory and that while you build them, no one of them both give you AP?? I mean you suck hard during the first 30 minutes of game and also you still need to charge Manamune! LOL

Please if you realize that in my guide are 3 kind of builds, you will see that [Rod of Ages]] is just in the ""Balance"" build!

Yup. Syndra is all about burst and RoA screws that completely. Muramana + Warmog's Armor gives the best of both worlds these days.

A large mana pool is way worse than high mana regen.

Rod of ages is not a famous item since long time, because people are pigeonholed in public input. In my opinion after the remake of the items is not the same. The cost has been lowered to 2800k and now Deathfire Grasp cost 3000k. Also gives HP, Mana <- syndra is a mana hungry and 80 AP. This item is not bad, is a normal one. Is choice of every single player build glass cannon or not, all depends of the team we are, and how is the situation.
Rod of ages can be build from "Catalyst the Protector" wich is very good in the early lane phase. Last but not least, a good pool of mana is also so good as mana regen, if not better. So 650 extra mana are very usefull without having to be afraid of running out of mana and expect to have to regenerate.

Rod of ages sucks on syndra.