I saw tonight that just one 1-watt Luxeon with Fraen 30-degree beamwidth collimator provides plenty of light for viewing at all magnifications of my Meiji EMZ zoom microscope. I would not want more brightness. I will still use four lights to eliminate shadows and soften specular reflections, but I'll definitely want brightness control. It might be interesting to be able to vary the brightness of each light. Maybe not having all lights the same brightness could be useful at times. Photographers often use several lights, often not all the same brightness or distance from the subject. .
Best convenience would be had by having the lights as close to the objective as possible, but I got better lighting with less specular confusion when I moved the light out radially 1" to 1.5" from the objective. An advantage I anticipate from a 4-light arrangement over a ringlight is having regions on both sides where nothing interferes with access. I've found that a ringlight that extends radially 2" from the objective sometimes gets in the way.