Disable a number of LW features to reduce combination pressure until we have proper keyword stripping.

ScriptableRenderPipeline/LightweightPipeline/LWRP/LightweightPipeline.cs

             int vertexLightsCount = lightData.totalAdditionalLightsCount - lightData.pixelAdditionalLightsCount;
 
             int mainLightIndex = lightData.mainLightIndex;
+            //TIM: Not used in shader for V1 to reduce keywords
+            //TIM: Not used in shader for V1 to reduce keywords
+
+
+            //TIM: Not used in shader for V1 to reduce keywords
+
             CoreUtils.SetKeyword(cmd, "_ADDITIONAL_LIGHTS", lightData.totalAdditionalLightsCount > 0);
             CoreUtils.SetKeyword(cmd, "_MIXED_LIGHTING_SUBTRACTIVE", m_MixedLightingSetup == MixedLightingSetup.Subtractive);
             CoreUtils.SetKeyword(cmd, "_VERTEX_LIGHTS", vertexLightsCount > 0);

ScriptableRenderPipeline/LightweightPipeline/LWRP/ShaderLibrary/Lighting.hlsl

 
 half4 GetMainLightDirectionAndAttenuation(LightInput lightInput, float3 positionWS)
 {
-    half4 directionAndAttenuation;
-
-#if defined(_MAIN_LIGHT_DIRECTIONAL)
-    directionAndAttenuation = half4(lightInput.position.xyz, 1.0);
-#else
-    directionAndAttenuation = GetLightDirectionAndAttenuation(lightInput, positionWS);
-#endif
+    half4 directionAndAttenuation = lerp(half4(lightInput.position.xyz, 1.0), GetLightDirectionAndAttenuation(lightInput, positionWS), lightInput.position.w);
 
     // Cookies are only computed for main light
     directionAndAttenuation.w *= CookieAttenuation(positionWS);
 
 void MixRealtimeAndBakedGI(inout Light light, half3 normalWS, inout half3 bakedGI, half4 shadowMask)
 {
-#if defined(_MAIN_LIGHT_DIRECTIONAL) && defined(_MIXED_LIGHTING_SUBTRACTIVE) && defined(LIGHTMAP_ON) && defined(_SHADOWS_ENABLED)
-    bakedGI = SubtractDirectMainLightFromLightmap(light, normalWS, bakedGI);
+#if defined(_MIXED_LIGHTING_SUBTRACTIVE) && defined(LIGHTMAP_ON) && defined(_SHADOWS_ENABLED)
+    bakedGI = lerp(SubtractDirectMainLightFromLightmap(light, normalWS, bakedGI), bakedGI, _MainLightPosition.w);
 #endif
 
 #if defined(LIGHTMAP_ON)

ScriptableRenderPipeline/LightweightPipeline/LWRP/Shaders/LightweightStandard.shader

 
             // -------------------------------------
             // Lightweight Pipeline keywords
-            #pragma multi_compile _MAIN_LIGHT_DIRECTIONAL _MAIN_LIGHT_SPOT
-            #pragma multi_compile _ _MAIN_LIGHT_COOKIE
             #pragma multi_compile _ _ADDITIONAL_LIGHTS
             #pragma multi_compile _ _VERTEX_LIGHTS
             #pragma multi_compile _ _MIXED_LIGHTING_SUBTRACTIVE

ScriptableRenderPipeline/LightweightPipeline/LWRP/Shaders/LightweightStandardSimpleLighting.shader

 
             // -------------------------------------
             // Lightweight Pipeline keywords
-            #pragma multi_compile _MAIN_LIGHT_DIRECTIONAL _MAIN_LIGHT_SPOT
-            #pragma multi_compile _ _MAIN_LIGHT_COOKIE
             #pragma multi_compile _ _ADDITIONAL_LIGHTS
             #pragma multi_compile _ _VERTEX_LIGHTS
             #pragma multi_compile _ _MIXED_LIGHTING_SUBTRACTIVE

ScriptableRenderPipeline/LightweightPipeline/LWRP/Shaders/LightweightStandardTerrain.shader

 
             // -------------------------------------
             // Lightweight Pipeline keywords
-            #pragma multi_compile _MAIN_LIGHT_DIRECTIONAL _MAIN_LIGHT_SPOT
-            #pragma multi_compile _ _MAIN_LIGHT_COOKIE
             #pragma multi_compile _ _ADDITIONAL_LIGHTS
             #pragma multi_compile _ _VERTEX_LIGHTS
             #pragma multi_compile _ _MIXED_LIGHTING_SUBTRACTIVE