However, this is really ugly, and it's Italian to boot:
You'll find that most highly experimental engines from anywhere draw bad reactions.
smoke box fronts: geometric shapes matter. modern NYC power was putrid (that's an understatement). Perhaps the ugliest locomotives ever built were their P&LE 2-8-4s.
It's interesting just how different we are. I count J3s, S1s, L4s and A2s all among the most attractive.
high mounted boilers, typically for the purpose of allowing a wider firebox without a trailing truck were barf inducing. If you're going to do without a rear truck, you better accept having a narrow firebox that sits in between the rear drivers...
This I can agree on. The worst offenders on this aren't American; the loading gauge in steam days wasn't high enough. Some classes of Russian 2-10-0 had so much airspace under the boiler you could almost walk through.
solid pilots are ugly...give me some sort of spokes or lattice!
For me, solid or footboard pilots look best. Cowcatcher-style pilots are alright if they don't extend too far. The most consistently ugly are pilots made of horizontal slats; these tend to ruin Argentine, Uruguayan and Paraguayan steam.
Most British and Italian steam looks too... well, clean, and I particularly don't like most British smokeboxes. German and French steam somehow looks finely engineered.
I tend to prefer semistreamlined steam to fully streamlined. I like, for example, CP steam with recessed headlights - the barely-streamlined Royal Hudsons and Selkirks, but actually more so their late heavy 4-6-2s and 2-8-2s which weren't even rounded off. Skyline casings are another weakness; favorites here are unstreamlined SP GS-series and AC-9s and East German 01.5s. Among unambiguously streamlined steam, those that still don't try to hide the shape (NYC Hudsons, N&W Js) come off much better than earlier shrouded efforts. In fact, it's questionable which are worst: the ugliest messy engines, or the most strained efforts to hide them.
EDIT: Just remembered what I was trying to, an example of what I'm talking about. DRG class 05 4-6-4s. The shroud made them unrecognizable as locomotives. I hate when streamlining hides the wheels.