PTI and Imran means something different to everyone.
Yes to some they hold Imran as some sort of savior who is moral and will lift Pakistan from darkness into a new age of enlightenment.
For me though and I presume many others others see him as the lesser of the three evils (four if you count army rule).
There are numerous bad things about PTI and Imran. There are some people who should have been kept away from the party to give PTI a moral legitimacy. Also, Imran is not a seasoned politician and made very amateur mistakes on the lead up to the election and then again during the dharnas.
Need to breakaway from rule by family dynasties. This is the biggest negative of PMLN and PPP. They fill their ranks with family members regardless of qualifications, this is not how governments should be run. Maryam and Bilawal are already both being groomed, need I say more

.
National debt is through the roof, rising every day.
PMLN failed to deliver on its most crucial campaign promise. They said they were going to eliminate load shedding. They haven't even come close.
Your next point was why doesn't Imran take on the army? Come on man, is there any person, organization, political party, anything within Pakistan that can take on the army? The army is untouchable, I do not expect Imran, Nawaz, or Zardari to be able to do anything against them.
Lets hold realistic expectations of these political parties and know their limitations within the domestic power structure. Battling corruption within the civilian government is perfectly within their limitations. Eliminating load shedding, etc... is also under their domain.