Pros:
Washington Park is, simply put, the best, most complete disc golf course in the immediate Indianapolis area. This course has an excellent design with great flow from hole to hole (for the most part) and very little fairway interference.
The course is an older course (which is part of why I appreciate it so much - but that is my own personal bias). As such it has older but adequate baskets (Machs), adequate tee signs, and has been well broken in.
The holes are each fairly different, keeping it interesting. The design makes excellent usage of the trees and small hills that can be found throughout the park.
The course also has at least one hole (#17)that is unique among the 80+ courses that I have played (and I mean unique in a good way).
The course boasts a nice variety with some lightly wooded holes, some wide open holes, and some technical holes in the woods.
While by no means easy, the course is short enough that it remains the only 18 hole course where I have ever broken par (perhaps that says more about me than the course!).
There is a kiosk at Hole #1 with a park map, though, for the most part, a map is not really a necessity here (which speaks again to the good design).
Cons:
The cons of this course are few and minor. There is only one bench on the course (Hole #13) and very few trash cans. While the signs and baskets are adequate, they are showing their age, especially with some of the older Mach baskets that have very shallow catchers. Also, Hole #12 is completely missing its sign.
The only real flow issues are between holes 3 and 4 (take a left at 3's basket), holes 11 and 12 (take another left at the basket, cross between 1's tee pad and 18's basket, and head toward the road and the missing sign), and between 12 and 13 (take another left at the basket, follow the road to the right, and take the wooden steps on the right). Directional signs would be an excellent addition to these spots. The only real backtracking on this course is after holing out on #16.
After heavy rains, this course gets wet (like all courses do) but also seems to stay wet for a while.
If you bring new players here, be aware that a decently-well traveled road is very much in play on holes 2-5, and especially on hole 12. There are also woods in play on holes 11 &12, and 16 & 17 as potential lost disc areas. A spotter is almost a must on Hole #17.
Due to the fact that this is an older course and that a couple of the basket placements are nicely on the sides of hills (3 and 6), there are some erosion problems that might be alleviated by the addition of a few alternate pin placements.
Some with bigger arms than I may not like the short distances throughout this course.
Honestly, there is nothing about this course that I complain about in any real sense. It is a pleasure to play.
Other Thoughts:
The course is divided into a front 11 and a back 7, and they are very different. The front is fairly straight forward, city-park type disc golf. The back is far more of an adventure.
Not coincidentally, the back features my 3 favorite holes: Hole 12 - a hole I have yet to figure out. I struggle to keep it in bounds and not in the woods; Hole 16 - a short tease of a hole that is far harder to birdie than it looks; and Hole 17 - a hole requiring an arm and a shot I do not possess, but that is fun and challanging nonetheless. As I said earlier, this hole is very unique in my disc golf experience.
Bottom line: Washington Park is a solid, well-balanced, complete disc golf experience. If you had time for only one course in Indy, this is the one.