I would love Machado at third and I have no issue going to ~300M over 10 years (its not my money). I think he will be worth it. I think he produces 5-6 WAR over the next 5-6 years barring injury which should cover his salary if we assume WAR is worth 9m. He may not have Harpers bat but hes not far behind and his defence is a massive upgrade over what we have in the infield.
Harper I think is going to get overpaid based on his name rather than what he has actually done. People are expecting a perennial MVP candidate but he is so weirdly inconsistent. He isn't a great defensive outfielder and may eventually end up at 1B, though not for 5 or 6 years.
If we could get Machado for 3B, and then Pollock and Brantley for the corners on 3-4 year deals you can add 10-12 WAR from those three players for something around 65M AAV, with flexibility in the outfield should Trout ever be a real possibility. I suspect Trout never comes to Philadelphia however but Pollock/Brantley wuld be relatively tradeable with 1-2 years left on their deals.
A everyday line up like this should be competitive in the NL East, with room for improvement. You can swap in Kingery for Hernandez if you think hes better.
I think the rotation needs strengthening, I suspect we'll see some regression from Nola and Eflin, and possibly VV and Pivetta. Basically everyone except for Arrieta who I think will benefit from an improved infield defence.
Adding Happ on a 2-3 year deal at ~15M and Morton on a 2 year deal at ~15 gives the Phillies a huge amount of starter depth. Klentak could look at trading Eflin, Velasquez, Hernandez, Franco, Williams and Altherr and see what return is available. Lottery tickets, starting pitching depth but with more options, young high strike out relivers all acceptable.
This may be a bit optimistic as I think Machado, Brantley, Pollock, Happ and Morton would add about 96M AAV. Baseball Ref is estimating the Phillies will be at 110.8M after arbitration. That brings salaries up to 206.8MM before trading anyone, with the luxury tax limit at 206M in 2019.
It might be doable by adding just one outfielder, or one pitcher, or by adding one of both and trading for another outfielder and starting pitcher on a lower salary.
I want to see the Phillies competing this year. They don't need to win the division, as it will be very difficult, but they need to be competitive and be in a position to compete for the next half decade at least.