As a Gen Xer I will give my opinion and perspective.
1. Nobody's listening to us - join the club!
It would be especially challenging for young people attending very huge megachurches. e.g.The size would make it next to impossible to have easy access to church leaders without appointments.
But young people - the church is not a club or social group. Ideally it should become a form of extended family. The church's primary purpose is to honour God and serve Him. A sign of that is through serving each other.
In stable families the roles are clearly determined. The parents lead, the children follow. The parents teach, the children learn. As they mature the children should be given more responsibility and opportunities to voice opinions on how things could be done better. Mature parents have no problems with that constructive feedback and so parents and children can learn and grow closer as they grow up too.
Brand new babes in Christ should be cared for much more carefully on an individual level, just like babies need so much 24/7 care at first. They should also realise just because they have a fine pair of lungs they do not have the right to express opinions at every opportunity. There needs to be a balance.
Young people who are not even Christians themselves are deluded if they think they still have the right to tell a church how they should do things better. It is not a social club. It is not your family.
2. Sick of Values and Mission Statements - there is a need for them but a far greater need that the beliefs stated are actually lived out. Actions speak louder than words.
3. Helping poor isn't a priority - helping the disadvantaged should be a goal of the church but not THE goal. Jesus said to his disciples they were go out into the world and preach the Gospel.
https://www.biblegateway.com/passage/?search=Matthew+28:18-20&version=KJV
If a church is substituting good works for preaching they are not following the above commandment. Taken to the extreme it becomes another gospel- the social Gospel.
http://www.bibletruths.net/Archives/BTAR283.htm
4. Tired of you blaming the culture - Absolutely agree 100%. Stop blaming the world for the church's failings and call it what it is - SIN. Expose sin for what it is and give us the remedy, Christ.
5. The you can't sit with us effect - another 100%. One weakness that some Christians who have been brought up in Christian families is they don't realise how different we outsiders feel to them. We already feel unsure and self-conscious - when no indication of interest in us is given we question even more if we should be there. There are no easy answers to this one - some megachurches might appear more welcoming to strangers than tiny ones (or vice versa) due to *the people themselves* in the church.
Personally I try to be friendly to newcomers as I know how hard it can be to even turn up it is from moving around so much and being so introverted myself.
6. Distrust and misallocation - another 100%. People have a right to know their money is being used responsibly. Even corporations have to show their investors their books, what makes some churches think they should be exempt?
7. Mentored, not preached at - should be "mentored AND preached at". Probably the point where the author sounded most immature. Preaching's purpose is inform listeners about God/ the bible, not your felt needs.
Mentoring should be done outside the church service timeslot.
8. We want to feel valued - as does everyone else. Encouragement is a powerful motivating tool.
9. We want to hear about controversial issues - that has it be done with great care. A pastor has to think of all age groups who will be listening to him. Some subjects would be better covered in youth groups or young adult bible studies.
In my opinion this is an area where the internet can be a great tool IF used wisely in the church ministry. e.g. The pastor Jason Cooley covers this area well. "Pornography is mind control".
http://www.sermonaudio.com/sermoninfo.asp?SID=32915183402
10. Public perception - the one area I disagree. The Seeker-Sensitive approach has backfired big-time. No matter how hard Christians try we will be hated by some people BECAUSE we are Christians.
Do public good deeds for GOD, not positive feedback from outsiders. Love your neighbour to show love for God.
11. Stop talking about us - agree. The preacher should be talking about God first.
Christians should be helping people who are weak or immature too.
12. You're failing to adapt- has priorities wrong. Preachers doing their job will keep doing the same and preaching the same message. JESUS hasn't changed. The bible hasn't changed. Preachers need to learn Millennials' worldview though and to get on their wavelength.