JTD-DesignerSeries-5-LightningExperience

What are upgrades, greenfield ?
In enterprise ecosystem, I have worked on quite a few upgrade projects, some small where we are retrofitting the code to support versioning, patches with 3-6 month timeframe, ; some medium where some of the major components of an application are re-written along with framework upgrades with 6-18 months timeframe; and then there are transformations initiatives that runs from top to bottom for several years in phases, re-define business processes & impact several applications.
I think Lightning Experience upgrades can fit in any of these buckets and for enterprises not having classic environments can go with greenfield, though existing classic implementation can start with partial greenfield for a business unit to taste lightning without impacting classic users.

Lightning Experience
It is quite huge and umbrella term for lot of features & services, through simply it's a salesforce way improving productivity for different personas, making application more aesthetic & beautiful, better positioning for its platform & services with trends like mobile, social.
a) As a user, Lightning experience is a different feel where features & services are easily accessible with efficient navigation, handy notes & recent items, cool layouts, list view & dashboards. Coarse grained features like Home Pages, Opportunity Workspace, Accounts & Contacts etc have been configured with new underlying components like Assistant, news supported with customizable view layer of List Views, Kanban Views. Users can even configure apps with custom branding & styling, communicate faster with better integration with gmail, outlook etc.
b) Lightning Experience not just focuses on improving the experience for all personas in Salesforce ecosystem, there is significant investment in lightning adoption tools like Lightning Experience Readiness Check, Optimizer, Switcher, shared & configurable components like Path, Timeline, Notes etc.
c) Lightning Experience, though really transformational with a forward looking vision, keeps the core of the application still intact by reusing existing Object Management Layer, supporting & improving platform technologies like Visualforce, Apex and helping architect & developers innovate with app centric & component based architectures.

Lightning Experience Features
I. Setup & Navigation
a) Setup has improved quite a bit in Lightning Experience with simple navigable structure, broad categories [Administration, Platform Tools, Settings], better tree nodes, quick find, alphabetic ordering.
b) App Launcher & Navigation Bar not only helps with consistent & simple UX across several apps, but also allow apps to have contain specific object tabs, dashboards & custom color & logos.
c) Better search capabilities with global search box on each page, object specific searches & refining the search results with filters.
d) Object Manager is one place where you can manage all your standard & custom objects, their related functions [Fields & Relationships, Page Layouts, Record Types, Validation Rules, Buttons & Links....]
e) Service Setup flows offers a guided step-by-step experience to walk you through setting up email support, integrating with Twitter and Facebook, enabling a knowledge base, and creating an online community.
II. Lightning Sales Tools
a) Sales Apps are enhanced with action based workspace [Opportunity Workspace] with customizable Path & Activity Timeline components.
b) Opportunity Kanban view organize sales rep deals by Stage in the pipeline and sales reps can easily toggle between list grid view & kanban view.
c) Leads Workspace eases qualifying & converting leads for Sales Reps.

d) Accounts & Contacts have been optimized with components like Highlight Panel, News & Twitter Integration, Hierarchy Views, contact to multiple accounts settings.

III. Lightning Customizations

a) Lightning Apps can be configured with most standard objects, custom objects, Visualforce tabs, lightning components & lightning pages tabs.
b) Lightning App Builder can customize Home Pages, configure lightning components visibility to create dynamic lightning pages.
c) Lightning Experience also supports customization of List Views, Record Pages, Compact Layouts, Buttons & Actions.

Lightning Experience Rollout
Rollout Approach provided by Salesforce follows three steps:

I. Discover

[Are Stakeholder onboard, Do we know the impact on existing functions, Have we done the gap analysis, What features can we get right away, Are we ready]

II.Roll Out

[How we are phasing the rollout, What is the feedback from pilot users, What we should test & How to measure success, Create Mitigation Plans, Communication & Training, Go-Live]

III. Optimize

[Gather Feedback from Business Users, Monitor Metrics, Weekly Executive Reports & Summary, Execute Mitigation & Stabilization Projects, Celebrate on Successful Rollouts]

Links & References
a) https://trailhead.salesforce.com/modules/lex_migration_introduction
b) https://trailhead.salesforce.com/en/modules/lex_customization
c) https://trailhead.salesforce.com/modules/lex_migration_whatsnew
d) https://trailhead.salesforce.com/en/modules/lex_migration_rollout