I'm late to the initial discussion, but I finished orc chapter a couple weeks ago and, other than about 2 weeks of being tech locked in the beginning - which is when I was only upgrading my orc buildings and portal, I sailed through that chapter the rest of the way.
Keep in mind, I have lots of time on my hands, and I usually do rounds every 3 hours. I think that makes quite a difference, in addition to the number of buildings you're able to have space for.
In my city, I had 4 rally points fully upgraded, 3 armories fully upgraded (though I imagine I could scale that back to 2 if I really wanted), and 42 mushroom farms upgraded only to level 2. If I didn't have space for that many, I would've cut that number in half and fully upgraded them. So the way a city is created can make quite a difference, and the amount of time upgrading can also make a difference.
I did not delete anything in my city except my steel manufactories, taking them down to 4.
I seriously doubt I could've made it through the orc chapter any faster, as you can only earn so much KP without spending diamonds (which I didn't do). But that chapter really didn't take me any longer than the fairy or dwarf chapters, but by maybe a couple weeks. So I honestly don't understand why people complained so much. I think in the end, it matters how much time you have to devote to the game. If you don't constantly harvest and reset the rally points, it will take a lot longer I imagine.
Also, it's so tempting to unlock the tech first, and I think that's a big mistake and adds time. Resist temptation, upgrade the orc buildings as soon as you can. The rest is bound to be smooth sailing.
That's my 2 cents =)