I just returned tonight from a hiking trip in the Rockies, and I was in Waterton Lakes NP for 5 days. The hikes we did and photographic opportunities in my opinion:
Crypt Lake - great hike, tedious ascent below treeline though. lake isn't that photogenic due to lack of icebergs and snow. waterfall is nice.
Carthew Alderson - really great hike, with plenty of photo ops. we hiked an additional 200 vertical metres to the summit of Mt Carthew, which has a nice view of the Alderson lakes and surrounding area.
Rowe Lakes trail - we only hiked up to the base of Mt. Lineham, and then scrambled to the summit, so i can't comment too much on the rest of the hiking trail. the view from the summit was great, with impressive peaks in the US looming in the background.
Wall/Forum lakes - we wanted to do the Akamina Ridge trail, but it was closed, so we just explored a little ice block above Wall lake. if you decide to check it out, the photo ops there are incredible. the ice is hollowed out, and it constantly drips from the ceiling in a large cascading waterfall.
We were there Aug 20-24 and conditions steadily improved from bad on the 20th to excellent on the 23rd. Conditions do vary but I wouldn't expect that much smoke left in the area. We had crazy winds that pretty much blew all of the smoke away from the park.
The nicest part of the smoke photo-wise is that you get sunset hues when the sun is still very high in the sky. We stayed at the Crandell Lake campground and got nice views of the surrounding mountains every day.
I haven't yet prepared my photos for viewing yet, but I can let you know when I do (within a week, hopefully)
My email is eric.degiuli ( at ) utoronto.ca